An article in Knee Surgery, Sports Traumatology, Arthroscopy, "Arthroscopic meniscal repair with an absorbable screw: results and surgical technique," (2005, Vol. 13, pp. 273-279) cites a success rate more than 90% for meniscal tears with a rim width of less than 3 mm, but only a 67% success rate for tears of 3-6 mm. If you are unlucky enough to suffer a meniscal tear of less than 3 mm on your left knee, and one of width 3-6 mm on your right knee, what are the mean and variance of the number of successful surgeries?

Answers

Answer 1

Answer:

Mean = 1.57

Variance=0.31

Step-by-step explanation:

To calculate the mean and the variance of the number of successful surgeries (X), we first have to enumerate the possible outcomes:

1) Both surgeries are successful (X=2).

[tex]P(e_1)=0.90*0.67=0.603[/tex]

2) Left knee unsuccessful and right knee successful (X=1).

[tex]P(e_2)=(1-0.9)*0.67=0.1*0.67=0.067[/tex]

3) Right knee unsuccessful and left knee successful (X=1).

[tex]P(e_3)=0.90*(1-0.67)=0.9*0.33=0.297[/tex]

4) Both surgeries are unsuccessful (X=0).

[tex]P(e_4)=(1-0.90)*(1-0.67)=0.1*0.33=0.033[/tex]

Then, the mean can be calculated as the expected value:

[tex]M=\sum p_iX_i=0.603*2+0.067*1+0.297*1+0.033*0\\\\M=1.206+0.067+0.297+0\\\\M=1.57[/tex]

The variance can be calculated as:

[tex]V=\sum p_i(X_i-\bar{X})^2\\\\V=0.603(2-1.57)^2+(0.067+0.297)*(1-1.57)^2+0.033*(0-1.57)^2\\\\V=0.603*0.1849+0.364*0.3249+0.033*2.4649\\\\V=0.1115+0.1183+0.0813\\\\V=0.3111[/tex]

Answer 2

The mean and variance of the number of successful surgeries for both knees combined are:

Mean: [tex]\({1.57}\)[/tex]

Variance: [tex]\({0.3111}\)[/tex]

The mean and variance of the number of successful surgeries for the given meniscal tears can be calculated using the information provided about the success rates.

For a meniscal tear with a rim width of less than 3 mm, the success rate is more than 90%. For simplicity, let's assume the success rate is exactly 90% (since we don't have the exact number above 90%). For a tear of 3-6 mm, the success rate is 67%.

Let's denote the success of a surgery as a random variable [tex]\( X \)[/tex], which takes the value 1 if the surgery is successful and 0 if it is not. The probability of success [tex]\( P(X = 1) \)[/tex] is the success rate, and the probability of failure [tex]\( P(X = 0) \)[/tex] is [tex]\( 1 - P(X = 1) \)[/tex].

For the left knee (tear less than 3 mm):

- [tex]\( P(X = 1) = 0.90 \)[/tex] (success rate)

- [tex]\( P(X = 0) = 1 - 0.90 = 0.10 \)[/tex] (failure rate)

For the right knee (tear 3-6 mm):

- [tex]\( P(X = 1) = 0.67 \)[/tex] (success rate)

- [tex]\( P(X = 0) = 1 - 0.67 = 0.33 \)[/tex] (failure rate)

The mean (expected value) of the number of successful surgeries for each knee is calculated as follows:

For the left knee:

[tex]\[ E(X) = \sum_{i=0}^{1} x_i \cdot P(X = x_i) = 1 \cdot 0.90 + 0 \cdot 0.10 = 0.90 \][/tex]

For the right knee:

[tex]\[ E(X) = \sum_{i=0}^{1} x_i \cdot P(X = x_i) = 1 \cdot 0.67 + 0 \cdot 0.33 = 0.67 \][/tex]

The variance of the number of successful surgeries for each knee is calculated using the formula for the variance of a binary random variable:

For the left knee:

[tex]\[ \text{Var}(X) = E(X^2) - [E(X)]^2 \][/tex]

[tex]\[ E(X^2) = \sum_{i=0}^{1} x_i^2 \cdot P(X = x_i) = 1^2 \cdot 0.90 + 0^2 \cdot 0.10 = 0.90 \][/tex]

[tex]\[ \text{Var}(X) = 0.90 - (0.90)^2 = 0.90 - 0.81 = 0.09 \][/tex]

For the right knee:

[tex]\[ E(X^2) = \sum_{i=0}^{1} x_i^2 \cdot P(X = x_i) = 1^2 \cdot 0.67 + 0^2 \cdot 0.33 = 0.67 \][/tex]

[tex]\[ \text{Var}(X) = E(X^2) - [E(X)]^2 \][/tex]

[tex]\[ \text{Var}(X) = 0.67 - (0.67)^2 = 0.67 - 0.4489 = 0.2211 \][/tex]

Now, assuming the surgeries on the two knees are independent events, the mean and variance for both knees combined can be calculated as follows:

Mean for both knees:

[tex]\[ E(X_{\text{left}} + X_{\text{right}}) = E(X_{\text{left}}) + E(X_{\text{right}}) = 0.90 + 0.67 = 1.57 \][/tex]

Variance for both knees:

Since the surgeries are independent, the variance of the sum is the sum of the variances:

[tex]\[ \text{Var}(X_{\text{left}} + X_{\text{right}}) = \text{Var}(X_{\text{left}}) + \text{Var}(X_{\text{right}}) = 0.09 + 0.2211 = 0.3111 \][/tex]

Therefore, the mean and variance of the number of successful surgeries for both knees combined are:

Mean: [tex]\({1.57}\)[/tex]

Variance: [tex]\({0.3111}\)[/tex]


Related Questions

The probability that a person in the United States has type B​+ blood is 13​%.
Four unrelated people in the United States are selected at random.
Complete parts​ (a) through​(d).

(a) Find the probability that all four have type B​+ blood.The probability that all four have type B​+ blood is?
​(Round to six decimal places as​ needed.)
​(b) Find the probability that none of the four have type B​+ blood.The probability that none of the four have type B​+ blood is?
​(Round to three decimal places as​ needed.)
​(c) Find the probability that at least one of the four has type B​+ blood.The probability that at least one of the four has type B​+ blood is?
​(Round to three decimal places as​ needed.)
​(d) Which of the events can be considered​ unusual? Explain. Select all that apply.
A.None of these events are unusualNone of these events are unusual.
B.The event in part​ (a) is unusual because its probability is less than or equal to 0.05.
C.The event in part​ (b) is unusual because its probability is less than or equal to 0.05.
D.The event in part​ (c) is unusual because its probability is less than or equal to 0.05.

Answers

a) Probability that all four have type B+ blood = 0.00031213

b) Probability that none of the four have type B+ blood = 0.57289761

c) Probability that at least one of the four has type B+ blood = 0.42710239

d) B. The event in part (a) is unusual because its probability is less than or equal to 0.05.

To solve these probability problems, we'll use the binomial probability formula:

[tex]P(X=k) = (n, k) \times p^k \times (1-p)^{(n-k)[/tex]

Where:

P(X=k) is the probability of having exactly k successes in n trials.

(n choose k) is the number of ways to choose k successes from n trials (n! / (k! (n-k)!), where n! is the factorial of n).

p is the probability of success (having type B+ blood in this case).

q = 1 - p is the probability of failure (not having type B+ blood).

n is the number of trials.

Given:

p = 0.13 (probability of having type B+ blood)

q = 1 - p = 0.87 (probability of not having type B+ blood)

n = 4 (number of trials)

Let's solve each part step by step:

(a) Probability that all four have type B+ blood:

[tex]P(X=4) = (4, 4) \times 0.13^4 \times 0.87^{(4-4)[/tex]

[tex]P(X=4) = 1 \times 0.00031213 \times 1 \\\\= 0.00031213[/tex]

(b) Probability that none of the four have type B+ blood:

[tex]P(X=0) = (4, 0) \times 0.13^0 \times 0.87^4 \\\\P(X=0) = 1 \times 1 \times 0.57289761 \\\\= 0.57289761[/tex]

(c) Probability that at least one of the four has type B+ blood:

P(at least one) = 1 - P(none)

P(at least one) = 1 - 0.57289761

= 0.42710239

Now, let's determine which events are considered unusual. Generally, an event with a probability less than or equal to 0.05 is considered unusual.

Let's compare the probabilities:

Probability in part (a): 0.00031213 (less than 0.05)

Probability in part (b): 0.57289761 (greater than 0.05)

Probability in part (c): 0.42710239 (greater than 0.05)

Based on the comparison, the only event that can be considered unusual is the event in part (a) because its probability is less than 0.05. Therefore, the correct answers are:

B. The event in part (a) is unusual because its probability is less than or equal to 0.05.

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Final answer:

The calculations show that the probability of all four people having B+ blood is 0.000028561, and the likelihood of none of them having B+ blood is 0.569532. The chance of at least one of them having B+ blood is 0.430468. Thus, only the event in part (a) is considered unusual due to its low probability.

Explanation:

This question is about using probability principles to figure out the likelihood of having certain blood types in a population.

(a) To find the probability that all four individuals have type B+ blood, we need to multiply the individual probabilities together. The probability that one person has B+ blood is given as 13% or 0.13. So, the probability that all four have B+ blood is 0.13*0.13*0.13*0.13 = 0.000028561.

(b) The probability that none of the four have type B+ blood is the complement of the probability that one person has B+ blood. This is 1 - 0.13 = 0.87. We now raise this to the power of four to find the probability that all four selected people do not have B+ blood: 0.87*0.87*0.87*0.87 = 0.569532.

(c) The probability that at least one has type B+ blood is the complement of the result in part b. We subtract our answer from part b from 1: 1 - 0.569532 = 0.430468.

(d) An event is considered unusual if its probability is less than or equal to 0.05. Here, the event in part (a) is unusual because its probability (0.000028561) is less than or equal to 0.05.

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Researchers are interested in studying how to maintain weight loss. Based on a survey of almost 3000 adults, researchers Wyatt et al. (Obesity Research, 2002) reported that those who ate breakfast regularly tended to be more successful at maintaining their weight loss. Based on this study, could we conclude "eating breakfast regularly" and "maintaining weight loss" are in the "cause-and-effect relationship? Give reasons to support your answer

Answers

Answer:

No , the cause and effect can be finished up through analyses as it were.  

What we have in the inquiry is only an observational investigation where we basically study 3000 grown-ups and attempt to outline the outcomes with no trial proof.  

Imagine a scenario in which individuals who had breakfast normally were inclined to maintain their weight reduction, for sure if individuals who keep up weight reduction will in general have breakfast routinely.  

henceforth the circumstances and logical results relationship cannot be built up  

So as to do so , one must lead measurable trials, for example, autonomous example t test or ANOVA examination

MARSVECTORCALC6 3.4.020. My Notes A rectangular box with no top is to have a surface area of 64 m2. Find the dimensions (in m) that maximize its volume.

Answers

Answer:

We would have

                                    [tex]l =w =\frac{8\sqrt{3}}{3} \\h = \frac{8\sqrt{3}}{6}[/tex]

where " l " is  length, " w"  is width and "h" is height.

Step-by-step explanation:

Step 1

Remember that

         Surface area for a box with no top = [tex]lw+2lh+2wh = 64[/tex]

where " l " is  length, " w"  is width and "h" is height.

 Step 2.

Remember as well that

                              Volume of the box = [tex]l*w*h[/tex]

Step 3

 We can now use lagrange multipliers.  Lets say,

                                    [tex]F(l,w,h) = lwh[/tex]

and

                                [tex]g(l,w,h) = lw+2lh+2wh = 64[/tex]

By the lagrange multipliers method we know that                            

 

                                                     [tex]\nabla F = \lambda \nabla g[/tex]

Step 4

Remember that

                          [tex]\nabla F = (wh,lh,lw)[/tex]

and

                      [tex]\nabla g = (w+2h,l+2h , 2w+2l)[/tex]

So basically you will have the system of equations

                              [tex]wh = \lambda (w+2h)\\lh = \lambda (l+2h)\\lw = \lambda (2w+2l)[/tex]

Now, remember that you can multiply the first eqation, by "l" the second equation by "w" and the third one by "h" and you would get

                                   [tex]lwh = l\lambda (w+2h)\\\\lwh = w\lambda (l+2h)\\\\lwh = h\lambda (2w+2l)[/tex]

Then you would get

                      [tex]l\lambda (w+2h) = w\lambda (l+2h) = h\lambda (2w+2l)[/tex]

You can get rid of [tex]\lambda[/tex] from these equations and you would get

                         [tex]lw+2lh = lw+2wh = 2wh+2lh[/tex]

And from those equations you would get

                                             [tex]l = w =2h[/tex]

Now remember the original equation

                                    [tex]lw+2lh+2wh = 64[/tex]

If we plug in what we just got, we would have

                                 [tex]l^{2} + l^{2} + l^2 = 64 \\3l^{2} = 64 \\l = w = \frac{8\sqrt{3} }{3} \\h = \frac{8\sqrt{3} }{6}[/tex]

                       

                                                 

Final answer:

To maximize the volume of an open-topped rectangular box with a fixed surface area, express the volume in terms of a single variable using the provided surface area equations. Solve these using calculus methods to find the maximum volume.

Explanation:

This question involves the field of mathematics, specifically calculus and optimization. As the task is about maximizing the volume of an open-topped rectangular box with a fixed surface area, we can look into the relation between length, width, height, surface area, and volume of the box.

Let's denote the length of the box as x, width as y, and height as z. The volume (V) of a the box is found by multiplying length, width, and height: V = xyz.

Since there is no top, the surface area (A) is calculated by adding together the areas of the bottom and the four sides, which gives us: A = xy + 2xz + 2yz = 64 m².

To maximize the volume, we need to express the volume in terms of a single variable. From the surface area equation, we can solve for z to get: z = (64 - xy) / (2x + 2y). Now substitute z into the volume equation to get V = xy * [(64 - xy) / (2x + 2y)]. Now we can take derivative of V with respect to x and y, set that equal to zero and find when the volume will be maximum. After solving, we will find the dimensions that maximize the volume of the box under given condition.

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A corporation must appoint a president, chief executive officer (CEO), chief operating officer (COO), and chief financial officer (CFO). It must also appoint a planning committee with four different members. There are 15
qualified candidates and officers can also serve on the committee.
Complete parts (a) through (c) below.

a. How many different ways can the officers be appointed?
There are nothing different ways to appoint the officers.
b. How many different ways can the committee be appointed?
There are nothing different ways to appoint the committee.
c. What is the probability of randomly selecting the committee members and getting the five youngest of the qualified candidates?
P(getting the five youngest of the qualified candidates)equals=nothing

Answers

Answer:

a. 32,760 ways

b. 1365 ways

b. 1/1365

Step-by-step explanation:

Given

Number of qualified candidates= 15

Number of Vacancies = 4 ( President, CEO, COO and CFO)

a.

How many different ways can the officers be appointed?

This means that in how many ways can 4 candidates be arranged out of a total of 15.

They keyword here is arranged which means Permutation because the order of arrangement doesn't count.

So,

Number of Appointments = 15P4

Number of Appointment = 1365 ways

b. How many different ways can the committee be appointed?

Here, the order of appointments matters.

So, this means, in his many ways can a committee of 4 be selected out of a total of 15.

The keyword, selection means Combination.

So, number of Appointments = 15C4

Number of Appointments = 1365

c. What is the probability of randomly selecting the committee members and getting the five youngest of the qualified candidates?

There are 1365 ways of choosing the board members and the chance of selecting the 5 youngest members is 1, because there's only one way to select the 5 youngest.

So the probability = 1/1365

Final answer:

To appoint officers, there are 32,760 different ways. The committee can be appointed in 1,365 different ways. The probability of randomly selecting the four youngest candidates for the committee is approximately 0.073%.

Explanation:

To solve the problem of appointing corporate officers and a committee, we will go step by step. For part (a), there are 15 qualified candidates, and we need to appoint 4 different officers. Since one person cannot hold more than one officer position simultaneously, we will use permutations. The first officer can be chosen in 15 ways, the second in 14 ways, the third in 13 ways, and the fourth in 12 ways, making the total number of ways to appoint the officers:

15 × 14 × 13 × 12 = 32,760 different ways.

For part (b), after appointing the officers, 11 candidates remain (15 total candidates - 4 officers). However, since officers can also serve on the committee, we still have 15 candidates to choose from. We need to appoint 4 different committee members from these 15 candidates, which is a combination problem because the order in which they're chosen doesn't matter. The number of ways to appoint the committee is given by the combination formula C(n, k) = n! / (k!(n-k)!), where n is the total number of candidates, and k is the number of positions to fill:

C(15,4) = 15! / (4!(15-4)!) = 15! / (4! × 11!) = (15 × 14 × 13 × 12) / (4 × 3 × 2 × 1) = 1,365 different ways.

For part (c), to find the probability of randomly selecting the five youngest candidates of the 15 qualified candidates, we should note that there are 4 positions on the committee, not 5. Assuming 'five youngest' is a typo, the probability of getting the 4 youngest candidates on the committee is:

P(selecting 4 youngest) = 1 / C(15, 4) = 1 / 1,365 ≈ 0.00073, or 0.073%.

In a study of feeding behavior, zoologists recorded the number of grunts of a warthog feeding by a lake in a 15 minute time period following the addition of food. The data showing the weekly number of grunts and the age of the warthog (in days) are listed below. Compute the sum of the squared residuals of the least squared line for the given data Week 1 Number of Grunts 90 age(days) 125 Week 2 Number of Grunts 68 age(days) 141 Week 3 Number of Grunts 39 age(days)155 Week 4 Number of Grunts 44 age(days)160 Week 5 Number of Grunts 63 age(days) 167 Week 6 Number of Grunts 40 Age(days) 174 Week 7 Number of Grunts 62 Age(days) 183 Week 8 Number of Grunts 17 Age(days) 189 Week 9 Number of Grunts 20 Age(days) 195 Can you please show me how to do this by hand I am not allowed to use a scientific calculator?

Answers

The sum of the squared residuals of the least squares line for the given data is 8691.90.

To compute the sum of the squared residuals for the given data, we will perform the steps of calculating the least squares line manually. The least squares line represents the linear regression line that minimizes the sum of the squared differences between the observed data points and the predicted values.

Week 1: Number of Grunts = 90, Age (days) = 125

Week 2: Number of Grunts = 68, Age (days) = 141

Week 3: Number of Grunts = 39, Age (days) = 155

Week 4: Number of Grunts = 44, Age (days) = 160

Week 5: Number of Grunts = 63, Age (days) = 167

Week 6: Number of Grunts = 40, Age (days) = 174

Week 7: Number of Grunts = 62, Age (days) = 183

Week 8: Number of Grunts = 17, Age (days) = 189

Week 9: Number of Grunts = 20, Age (days) = 195

Calculate the means of the Number of Grunts (Y) and Age (X) variables:

Mean of Y (Number of Grunts) = (90 + 68 + 39 + 44 + 63 + 40 + 62 + 17 + 20) / 9 = 48.78

Mean of X (Age) = (125 + 141 + 155 + 160 + 167 + 174 + 183 + 189 + 195) / 9 = 165

Calculate the deviations from the means for each data point:

For each data point, subtract the mean of X (Age) from the specific X value and the mean of Y (Number of Grunts) from the specific Y value.

Deviation from mean for each X value:

125 - 165.67 = -40.67

141 - 165.67 = -24.67

155 - 165.67 = -10.67

160 - 165.67 = -5.67

167 - 165.67 = 1.33

174 - 165.67 = 8.33

183 - 165.67 = 17.33

189 - 165.67 = 23.33

195 - 165.67 = 29

Deviation from mean for each Y value:

90 - 48.78 = 41.22

68 - 48.78 = 19.22

39 - 48.78 = -9.78

44 - 48.78 = -4.78

63 - 48.78 = 14.22

40 - 48.78 = -8.78

62 - 48.78 = 13.22

17 - 48.78 = -31.78

20 - 48.78 = -28.78

Calculate the sum of the products of the deviations:

Sum of (Deviation from mean for X * Deviation from mean for Y)

= (-40.67 * 41.22) + (-24.67 * 19.22) + (-10.67 * -9.78) + (-5.67 * -4.78) + (1.33 * 14.22) + (8.33 * -8.78) + (17.33 * 13.22) + (23.33 * -31.78) + (29.33 * -28.78)

= -5.02 + -0.90 + 1.04 + 0.27 + 18.95 + -73.14 + 228.44 + -739.97 + -845.44

= -1407.77

Calculate the sum of the squared deviations for X:

Sum of (Deviation from mean for X)^2

= (-40.67)^2 + (-24.67)^2 + (-10.67)^2 + (-5.67)^2 + (1.33)^2 + (8.33)^2 + (17.33)^2 + (23.33)^2 + (29.33)^2

= 16572.86

Calculate the sum of the squared residuals:

Sum of squared residuals = Sum of (Deviation from mean for Y)^2

= (41.22)^2 + (19.22)^2 + (-9.78)^2 + (-4.78)^2 + (14.22)^2 + (-8.78)^2 + (13.22)^2 + (-31.78)^2 + (-28.78)^2

= 8691.90

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The sum of the squared residuals of the least squared line for the given data is 8399.

To compute the sum of the squared residuals of the least squared line by hand, you will need to follow these steps:

1. Start by organizing the given data into two columns: one for the number of grunts and one for the age of the warthog.

Week 1: Number of Grunts = 90, Age (days) = 125

Week 2: Number of Grunts = 68, Age (days) = 141

Week 3: Number of Grunts = 39, Age (days) = 155

Week 4: Number of Grunts = 44, Age (days) = 160

Week 5: Number of Grunts = 63, Age (days) = 167

Week 6: Number of Grunts = 40, Age (days) = 174

Week 7: Number of Grunts = 62, Age (days) = 183

Week 8: Number of Grunts = 17, Age (days) = 189

Week 9: Number of Grunts = 20, Age (days) = 195

2. Calculate the mean (average) of the age and the number of grunts. To do this, add up all the values in each column and divide by the total number of data points.

Mean of the age (days):

(125 + 141 + 155 + 160 + 167 + 174 + 183 + 189 + 195) / 9 = 165

Mean of the number of grunts:

(90 + 68 + 39 + 44 + 63 + 40 + 62 + 17 + 20) / 9 = 52

3. Subtract the mean of the age from each age value to get the deviation of each data point from the mean. Similarly, subtract the mean of the number of grunts from each number of grunts value.

Deviation of the age:

125 - 165 = -40

141 - 165 = -24

155 - 165 = -10

160 - 165 = -5

167 - 165 = 2

174 - 165 = 9

183 - 165 = 18

189 - 165 = 24

195 - 165 = 30

Deviation of the number of grunts:

90 - 52 = 38

68 - 52 = 16

39 - 52 = -13

44 - 52 = -8

63 - 52 = 11

40 - 52 = -12

62 - 52 = 10

17 - 52 = -35

20 - 52 = -32

4. Square each deviation value obtained in step 3.

Squared deviation of the age:

[tex](-40)^2 = 1600[/tex]

[tex](-24)^2 = 576[/tex]

[tex](-10)^2 = 100[/tex]

[tex](-5)^2 = 25[/tex]

[tex]2^2 = 4[/tex]

[tex]9^2 = 81[/tex]

[tex]18^2 = 324[/tex]

[tex]24^2 = 576[/tex]

[tex]30^2 = 900[/tex]

Squared deviation of the number of grunts:

[tex]38^2 = 1444[/tex]

[tex]16^2 = 256[/tex]

[tex](-13)^2 = 169[/tex]

[tex](-8)^2 = 64[/tex]

[tex]11^2 = 121[/tex]

[tex](-12)^2 = 144[/tex]

[tex]10^2 = 100[/tex]

[tex](-35)^2 = 1225[/tex]

[tex](-32)^2 = 1024[/tex]

5. Sum up all the squared deviation values obtained in step 4.

Sum of squared residuals:

1600 + 576 + 100 + 25 + 4 + 81 + 324 + 576 + 900 + 1444 + 256 + 169 + 64 + 121 + 144 + 100 + 1225 + 1024 = 8399

Therefore, the sum of the squared residuals of the least squared line for the given data is 8399.

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The exam scores on a statistics final exam are normally distributed with a mean of 140 points out of 200 and standard deviation of 8. What is the probability that a randomly selected student scored less than 156 on the final exam

Answers

Answer:

Probability that a randomly selected student scored less than 156 on the final exam is 0.97725 .

Step-by-step explanation:

We are given that the exam scores on a statistics final exam are normally distributed with a mean of 140 points out of 200 and standard deviation of 8.

Let X = Score of students in exam

So, X ~ N([tex]\mu = 140, \sigma^{2} =8^{2}[/tex])

The z score probability distribution is given by;

           Z = [tex]\frac{X-\mu}{\sigma}[/tex] ~ N(0,1)

where, [tex]\mu[/tex] = population mean = 140

            [tex]\sigma[/tex] = standard deviation = 8

So, the probability that a randomly selected student scored less than 156 on the final exam is given by = P(X < 156)

 P(X < 156) = P( [tex]\frac{X-\mu}{\sigma}[/tex] < [tex]\frac{156-140}{8}[/tex] ) = P(Z < 2) = 0.97725 .

Therefore, the probability that a randomly selected student scored less than 156 on the final exam is 0.97725 .

To find the probability, calculate the z-score and look it up in a table or use a calculator. The probability of scoring less than 156 is approximately 0.9772.

To find the probability that a randomly selected student scored less than 156 on the final exam, we will use the z-score formula. The z-score formula is calculated by subtracting the mean from the given score and dividing by the standard deviation. In this case, the z-score is (156 - 140) / 8 = 2.

To find the probability, we can look up the z-score in a standard normal distribution table or use a calculator like the TI-84. Using either method, we find that the probability of a student scoring less than 156 is approximately 0.9772.

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When you generate a random number using your calculator, the random number you get is uniformly distributed over the interval (0, 1). Suppose 50 people in Stat 322 class generate one random number each (independently). X

Answers

Answer:

uniformly distributed random numbers here the MATLAB code to find for any number of people and interval

X = rand

X = rand(n)

X = rand(sz1,...,szN)

X = rand(sz)

X = rand(___,typename)

X = rand(___,'like',p)

where

X = rand returns a single uniformly distributed random number in the interval (0,1).

X = rand(n) returns an n-by-n matrix of random numbers.

X = rand(sz1,...,szN) returns an sz1-by-...-by-szN array of random numbers where sz1,...,szN indicate the size of each dimension. For example, rand(3,4) returns a 3-by-4 matrix.

X = rand(sz) returns an array of random numbers where size vector sz specifies size(X). For example, rand([3 4]) returns a 3-by-4 matrix.

X = rand(___,typename) returns an array of random numbers of data type typename. The typename input can be either 'single' or 'double'. You can use any of the input arguments in the previous syntaxes.

X = rand(___,'like',p) returns an array of random numbers like p; that is, of the same object type as p. You can specify either typename or 'like', but not both.

In an area of the Great Plains, records were kept on the relationship between the rainfall (in inches) and the yield of wheat (bushels per acre). Find the equation of the regression line for the given data.

Answers

Final answer:

The student's question pertains to calculating the regression line equation that represents the relationship between rainfall and wheat yield. This can be done using a calculator's statistical functions to provide the least-squares regression line equation, which allows for the prediction of one variable based on another.

Explanation:

The question asks about finding the equation for a linear regression line based on the relationship between rainfall and wheat yield. To accomplish this, one must enter the given data into a calculator, generate a scatter plot, and then use the calculator's regression function to find the least-squares regression line's equation. This regression equation typically takes the form î = a + bx, where 'a' is the y-intercept and 'b' is the slope of the line.

In terms of finding the regression line manually, a commonly used method is the median-median line approach, but for this question, we are instructed to use a calculator. The process involves statistical analysis to determine the line that minimally deviates from all data points in the scatter plot. Once the equation is calculated, one can predict values such as wheat yield for a given amount of rainfall.

You measure 33 textbooks' weights, and find they have a mean weight of 37 ounces. Assume the population standard deviation is 8.2 ounces. Based on this, construct a 95% confidence interval for the true population mean textbook weight.

Answers

Answer:

34.2022 < X < 39.7978

Step-by-step explanation:

For a 95% confidence interval, Z = 1.960

Sample size (n) = 33

Mean weight (X) = 37 ounces

Standard deviation (s) = 8.2 ounces

The relationship that describes a 95% confidence interval is:

[tex]X \pm 1.960*\frac{s}{\sqrt{n}}[/tex]

Applying the given data, the Lower (L) and Upper (U) limits are:

[tex]U=37 + 1.960*\frac{8.2}{\sqrt{33}} \\U=39.7978\\L=37 - 1.960*\frac{8.2}{\sqrt{33}} \\L=34.2022[/tex]

The 95% confidence interval is:

34.2022 < X < 39.7978

Find the probability that the proportion of individuals in the sample of 225 who hold multiple jobs is between 0.14 and 0.18. Round the answer to at least four decimal places. The probability that the proportion of individuals in the sample of 225 hold multiple jobs is between 0.14 and 0.18 i

Answers

Answer:

Step-by-step explanation:

Hello!

The variable of interest is X: number of individuals that hold multiple jobs in a sample of 225.

And you need to calculate the probability of the proportion of individuals being between 0.14 and 0.18.

Considering that the parameter of interest is the proportion and the sample is large enough you can use the standard normal approximation to calculate this interval.

[tex]Z= \frac{p'-p}{\sqrt{\frac{p(1-p)}{n} } }[/tex]

Unfortunately, there is no given value for the population proportion of individuals that have multiple jobs. Let's say, for example, that his proportion is 10%.

You can symbolize the probabilities as:

P(0.14≤X≤0.18)= P(X≤0.18)-P(X≤0.14)

Using the approximation of the standard normal you can standardize these proportion values:

P(Z≤(0.18-0.1)/√[(0.1*0.9)/225])-P(Z≤(0.14-0.1)/√[(0.1*0.9)/225])

P(Z≤4)-P(Z≤2)

Now you have to look for the corresponding values in the table of the Z distribution (right table, positive numbers of Z)

P(Z≤4)-P(Z≤2)= 1 - 0.97725= 0.02275

I hope it helps!

Answer:

0.1276

Step-by-step explanation:

Let sample space = S

∴ n(S) = 225

Probability of multiple jobs A, that is, P(A) = 0.14

Probability of multiple jobs B, that is, P(B) = 0.18

Hence, P(A) = n(A)/n(S)

∴ 0.14 = n(A)/225

n(A) = 0.14 X 225 = 31.5%

Also, P(B) = n(B)/n(S)

∴ 0.18 = n(B)/225

n(B) = 0.18 X 225 = 40.5%

The probability that the multiple jobs, P( A2 ∩ B2) = P(A2) X P(B2)

P(A2) = 0.315 and P(B2) = 0.405

∴ P(A2 ∩ B2) =  P(A2) X P(B2) = 0.315 X 0.405 = 0.1276

g Indicate whether the sequence is increasing, decreasing, non-increasing, or non-decreasing. The sequence may have more than one of those properties The nth term is 1/n.

Answers

Answer:

  decreasing, non-increasing

Step-by-step explanation:

The sequence is ...

  1, 1/2, 1/3, 1/4, ...

Each term is smaller than the one before it, so the sequence is decreasing (also, non-increasing).

After scoring a touchdown, a football team may elect to attempt a two-point conversion, by running or passing the ball into the end zone. If successful, the team scores two points. For a certain football team, the probability that this play is successful is 0.80.1. Let X = 1 if successful, X = 0 if not. Find the mean and the variance of X. Round the answers to two decimal places.The mean of X is = .The variance of X is =2. Let Y be the number of points scored. Find the mean and variance of Y. Round the answers to two decimal places.The mean of Y is =The variance of Y is =

Answers

Answer:

Step-by-step explanation:

given that after scoring a touchdown, a football team may elect to attempt a two-point conversion, by running or passing the ball into the end zone. If successful, the team scores two points.

X=1 if successful and

X=0 if not

pdf of X is

X      1       0

p    0.8   0.2

E(x) = [tex]1(0.8)+0(0.2)\\=0.8[/tex]

[tex]E(x^2) = 1^2(0.8) = 0.8[/tex]

Var(x) = 0.8-0.8*0.8

= 0.16

Now let us consider Y.

Y is the no of points scored.

Y      2       0

p     0.8    0.2

E(Y) = [tex]2(0.8)+0(0.2)\\=1,.6[/tex]

[tex]2^2(0.8)+0(0.2)\\= 3.2[/tex]

Final answer:

The mean and variance for X and Y are calculated using their definitions in probability theory. For X, the mean is 0.80 and variance is 0.16. For Y, the mean is 1.60 and variance is 0.64.

Explanation:

The random variable X is a Bernoulli random variable because it has only two outcomes: success (X=1) and failure (X=0). The mean and variance for a Bernoulli random variable can be found using the formulas: Mean (E[X]) = p and Variance (Var[X]) = p(1-p).

 For X:

The mean E[X] = p = 0.80. So, X = 1 with probability 0.80.

The variance Var[X] = p(1-p) = 0.80(1-0.80) = 0.16

The random variable Y represents the number of points scored which can either be 0 or 2. We let p be the probability of scoring 2 points i.e., p = 0.80. Hence, if the two-point conversion is successful, we will score 2 points, otherwise, we score 0.

For Y:

The mean E[Y] = 0*(1-p) + 2*p = 0 + 2*0.80 = 1.60

The variance Var[Y] = (0-E[Y])^2*(1-p) + (2-E[Y])^2*p = (0-1.60)^2*(1-0.80) + (2-1.60)^2*0.80 = 0.64

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1) A home improvement store sold wind chimes for w dollars each. A customer signed up for a free membership card and received a 5% discount off the price. Sales tax of 6% was applied after the discount. Write an algebraic expression to represent the final price of the wind chime.

Answers

Answer:

Step-by-step explanation:

The original price of the wind chimes at the home improvement store is $w.

A customer signed up for a free membership card and received a 5% discount off the price. The value of the discount is

5/100 × w = 0.05w

The discounted price would be

w - 0.05w = 0.95w

Sales tax of 6% was applied after the discount. The amount of sales tax applied would be

6/100 × 0.95w = 0.057w

The algebraic expression to represent the final price of the wind chime is

0.95w + 0.057w

= 1.007w

Rod is a drummer who purchases his drumsticks online. When practicing with the newest pair, he notices they feel heavier than usual. When he weighs one of the sticks, he finds that it is 2.33 oz. The manufacturer's website states that the average weight of each stick is 1.75 oz with a standard deviation of 0.22 oz. Assume that the weight of the drumsticks is normally distributed. What is the probability of the stick's weight being 2.33 oz or greater? Give your answer as a percentage precise to at least two decimal places.

Answers

Answer:

The probability of the stick's weight being 2.33 oz or greater is 0.41%.

Step-by-step explanation:

Test statistic (z) = (weight - mean)/sd

weight of stick = 2.33 oz

mean = 1.75 oz

sd = 0.22 oz

z = (2.33 - 1.75)/0.22 = 2.64

The cumulative area of the test statistic is the probability that the weight is 2.33 oz or less. The cumulative area is 0.9959.

The probability the weight is 2.33 or greater = 1 - 0.9959 = 0.0041 = 0.41%

A scientist runs an experiment involving a culture of bacteria. She notices that the mass of the bacteria in the culture increases exponentially with the mass increasing by 260% per week. What is the 1-week growth factor for the mass of the bacteria?

Answers

The growth factor for the mass of bacteria is 2.8 in 1 week.

Step-by-step explanation:

Step 1:

It is given that the bacteria in the culture increase by 260% per week. Now we assign values to get a better understanding. If there were 1,000 bacteria in the culture at the start of the week there would be 1,000 + 260% at the week's end = 1,000 + 2,600 = 3,600 at the week's end.

Step 2:

To calculate the growth factor, we calculate the difference between the present value and the past value and divide it by the past value.

Here the past value is 1,000 and the present value is 2,600.

Growth factor = [tex]\frac{difference in values}{past value} = \frac{3,600-1,000}{1000} = \frac{2,600}{1,000} = 2.6.[/tex]

So the growth factor is 2.6 per week.

The guidance system of a ship is controlled by a computer that has 3 major modules. In order for the computer to function properly, all 3 modules must function. Two of the modules have reliabilities of 0.97 and the other has a reliability of 0.99.

a) What is the reliability of the computer?

b) A backup computer identical to the one being used will be installed to improve overall reliability. Assuming the new computer automatically functions if the main one falls, determine the resulting reliability.

c) If the backup computer must be activated by a switch in the event that the first computer fails, and the switch has a reliability of 0.98, what is the overall reliability of the system? (Both the switch and the backup computer must function in order for the backup to take over.)

Answers

Answer:

a) 0.931491

b) 0.995307

c) 0.994030

Step-by-step explanation:

a) Since all components must be working, the reliability of the computer is the product of the reliability of the three components:

[tex]R_1 = 0.97*0.97*0.99\\R_1=0.931491[/tex]

b) The resulting reliability is now the reliability of the first computer, added to the possibility of failure of the first computer multiplied by the reliability of the second computer:

[tex]R= R_1 +(1-R_1)*R_2\\R= 0.931491+(1-0.931491)*0.97*0.97*0.99\\R=0.995307[/tex]

c) If a switch with reliability of 0.98 must be activated to turn on the second computer, the switch's reliability must be taken into account as follows:

[tex]R= R_1 +(1-R_1)*R_2*R_S\\R= 0.931491+(1-0.931491)*0.97*0.97*0.99*0.98\\R=0.994030[/tex]

The reliability of the system is simply its probability of not failing

(a) The reliability of the computer

This is the product of the reliabilities of the three modules.

So, we have:

[tex]R = 0.97 \times 0.97 \times 0.99[/tex]

[tex]R = 0.931491[/tex]

Approximate

[tex]R = 0.9315[/tex]

Hence, the reliability of the computer is 0.9315

(b) The reliability when a backup is used

In (a), the reliability of the computer is 0.9315

When the computer fails, the reliabilities of the other two are 1 - 0.9315 and 1 - 0.9315.

So, the reliability when a backup is used is calculated using the following complement rule

[tex]R = 1 - [(1 - 0.9315) \times (1 - 0.9315)][/tex]

[tex]R = 0.99530775[/tex]

Approximate

[tex]R = 0.9953[/tex]

Hence, the reliability of the computer when a backup is 0.9953

(c) The overall reliability of the system

In (a), the reliability of the computer is 0.9315.

Also, the reliability of the switch is 0.98

So, the reliability of the backup is:

[tex]R = 0.9315 \times 0.98[/tex]

[tex]R = 0.9129[/tex]

So, the overall system has:

Main computer with reliability of 0.9315 Back up of the computer system with reliability of 0.9129

The reliability of the overall system is then calculated using the following complement rule

[tex]R = 1 - [(1 - 0.9315) \times (1 - 0.9129)][/tex]

[tex]R = 0.9940[/tex]

Hence, the reliability of the overall system is 0.9940

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Dr. Sabbaghi is taking two flights today. The flight time for the first flight is Normally distributed with a mean of 90 minutes and a standard deviation of 3 minutes. The flight time for the second flight is Normally distributed with a mean of 110 minutes and a standard deviation of 4 minutes. His total flight time today has what type of distribution with what mean and standard deviation?

Answers

Answer:

[tex] E(Z) = E(X+Y) = E(X) +E(Y) = \mu_X +\mu_Y = 90+110=200[/tex]

[tex] Var(Z) = Var(X+Y) = Var(X) +Var(Y) +2 Cov(X,Y)[/tex]

Since X and Y are independent then [tex] Cov(X,Y) =0[/tex] and we have this:

[tex] Var(Z)= \sigma^2_X +\sigma^2_Y = 3^2 +4^2 = 9+16 =25[/tex]

And the deviation would be given by:

[tex] Sd(Z) = \sqrt{25}= 5[/tex]

And then the distribution for the total time would be given by:

[tex] Z= X+Y \sim N( \mu_Z= 200, \sigma_Z= 5)[/tex]

Step-by-step explanation:

For this case we can assume that X represent the flight time for the first filght and we know that:

[tex] X \sim N (\mu_X= 90. \sigma_x =3)[/tex]

And let Y the random variable that represent the time for the second filght and we know this:

[tex] Y \sim N(\mu_Y = 110, \sigma_Y =4)[/tex]

And we can define the random variable Z= X+Y as the total time for the two flights.

We can asume that X and Y are independent so then we have this:

[tex] E(Z) = E(X+Y) = E(X) +E(Y) = \mu_X +\mu_Y = 90+110=200[/tex]

[tex] Var(Z) = Var(X+Y) = Var(X) +Var(Y) +2 Cov(X,Y)[/tex]

Since X and Y are independent then [tex] Cov(X,Y) =0[/tex] and we have this:

[tex] Var(Z)= \sigma^2_X + \sigma^2_Y = 3^2 +4^2 = 9+16 =25[/tex]

And the deviation would be given by:

[tex] Sd(Z) = \sqrt{25}= 5[/tex]

And then the distribution for the total time would be given by:

[tex] Z= X+Y \sim N( \mu_Z= 200, \sigma_Z= 5)[/tex]

Admission for students is $4.00 and adults are $8.00 and a total of $1808 was made in sales. If there was 325 fans at the game, how many were adults and students?

Answers

Answer:

198 students and 127 adults

Step-by-step explanation:

In order to solve for the number of adults and students, we'll have to create a few variables.

's' will stand for students and 'a' will stand for adults.

We can make two equations with what we've been given:

4s + 8a = 1808
s + a = 325

We can use the subtraction method in order to solve this equation. Multiply the second equation by -4 (We do this in order to isolate one of the variables):

4s + 8a = 1808
-4s - 4a = -1300
____________
4a = 508

We simply added the two equations together. Divide both sides by 4 and:

a = 127

Now that we know the number of adults who attended, we can input this variable into the second equation:

s + a = 325
s + 127 = 325
s = 198

127 adults attended and 198 students attended.

Match the name of the sampling method descriptions given.

Situations:
1. ask all the students in your math class
2. pulling 50 names from a hat
3. dividing the population by Gender, and choosing 30 people of each gender
4. dividing by population by voting precinct, and sampling everyone in the precincts selected
5. surveying every 3rd driver coming through a tollbooth

a. Sampling Method
b. Cluster Stratified
c. Convenience Simple
d. Random Systematic

Answers

Convenience SimpleRandom SystematicStratifiedClusterSampling Method

Elaborating on the matching of the sampling method descriptions:

Asking all the students in your math class is an example of convenience sampling. Pulling 50 names from a hat is an example of random systematic sampling.Dividing the population by gender and choosing 30 people of each gender represents stratified sampling. In stratified sampling, the population is divided into distinct subgroups or strata, and samples are taken from each stratum in proportion to their representation in the population. Dividing the population by voting precinct and sampling everyone in the selected precincts is an example of cluster sampling. Surveying every 3rd driver coming through a tollbooth is a specific example of sampling method and does not fit into any of the listed categories.

To summarize, the correct matching would be:

c. Convenience Simpled. Random Systematicb. Stratifiedb. Clustera. Sampling Method

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1: d. Convenience

2: e. Simple random

3: c. Cluster

4: a. Stratified

5: b. Systematic

1. Convenience sampling (d):

This involves selecting people who are readily available or readily available. Pulling names out of a hat is an example of convenience sampling.

2. Simple random sampling (e):

This involves randomly selecting individuals from a population, with each individual having an equal chance of being selected. An example of simple random sampling is polling all students in a math class.

3. Cluster sampling (c):

This involves dividing the population into groups (clusters) and then randomly selecting some of those clusters to be included in the sample. Randomly selecting two tables in a dining room and surveying all the people at those tables is an example of cluster sampling.

4. Stratified sample(s):

This involves dividing the population into subgroups (strata) based on certain characteristics and then selecting samples from each subgroup. Dividing students by year and selecting 10 students from each year is an example of stratified sampling.

5. Systematic sampling (b):

This involves selecting every nth individual from the population, where n is determined by dividing the population size by the sample size.An example of systematic sampling is calling every [tex]15^{th}[/tex] phone number on every [tex]5^{th}[/tex] page of a phone book.

Complete question:

Match the names of the given sampling method descriptions.

Situation:

1. drawing 50 names from a hat

2. ask all the students in your math class

3. randomly select two tables in the dining room and examine all the people at those two tables

4. dividing all students according to grades and selecting 10 students from each grade

5. call every 15th phone number on every 5th page of the phone book

Sampling method:

a. Stratified

b. Systematic

c. Cluster

d. Convenience

e. Simple random

Computer chips often contain surface imperfections. For a certain type of computer chip, 9% contain no imperfections, 22% contain 1 imperfection, 26% contain 2 imperfections, 20% contain 3 imperfections, 12% contain 4 imperfections, and the remaining 11% contain 5 imperfections. Let X represent the number of imperfections in a randomly chosen chip. Is X discrete or continuous

Answers

X is a discrete random variable.

A discrete random variable can only take on specific, distinct values with gaps in between.

In this case, X represents the number of imperfections in a computer chip, and it can only take on integer values: 0, 1, 2, 3, 4, or 5.

These values are countable and separate, indicating that X is a discrete random variable.

In contrast, a continuous random variable would have an infinite number of possible values within a range, and you would typically use intervals or real numbers to describe it.

For example, if we were measuring the weight of computer chips, it could be a continuous random variable because it could take on any value within a range, including fractions or decimals.

However, in this scenario, we are dealing with a countable and finite set of values for the number of imperfections, making X a discrete random variable.

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The area of a rectangle is represented by the function x3 − 2x2 − 40x − 64. The width of the rectangle is x + 4. Find the expression representing the length of the rectangle.

Answers

Answer: Length = x² - 6x - 16

Step-by-step explanation:

The formula for determining the area of a rectangle is expressed as. Area = length × width

Length = Area/width

The area of a rectangle is represented by the function

x³ - 2x² - 40x - 64. The width of the rectangle is x + 4. Therefore,

Length = (x³ - 2x² - 40x - 64)/(x + 4)

We would apply the method of long division. The steps are shown in the attached photo. From the photo,

Length = x² - 6x - 16

Hey love! <3

Answer:

⋆ ☄.

·˚ * I see your answer up in the stars! It's x^2 − 6x − 16 or C on your FLVS quiz!

Step-by-step explanation:

If area = length * width and our width is given as x + 4, then the length is found by dividing the area by the width; You could do that using long division, but it's easier using synthetic division. That's what we'll do here for example.

-4 |   1   -2   -40   -64  

This is only the start! The -4 inside the box comes from the factor you are dividing by. If x + 4 = 0, then x = -4.. The numbers after are the coefficients from each descending power of x. Multiply the -4 by the 1 and put that product up under the -2 and add to get:

-4 |   1   -2   -40   -64

After you finish the multiplication and simplification process you receive your given answer = x^2 − 6x − 16

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Professor Jennings claims that only 35% of the students at Flora College work while attending school. Dean Renata thinks that the professor has underestimated the number of students with part-time or full-time jobs. A random sample of 83 students shows that 38 have jobs.
Do the data indicate that more than 35% of the students have jobs? Use a 5% level of significance.
What is the value of the sample test statistic? (Round your answer to two decimal places.)

Answers

Answer:

[tex]z=\frac{0.458 -0.35}{\sqrt{\frac{0.35(1-0.35)}{83}}}=2.06[/tex]  

[tex]p_v =P(z>2.063)=0.020[/tex]  

So the p value obtained was a low value and using the significance level given [tex]\alpha=0.05[/tex] we have [tex]p_v<\alpha[/tex] so we can conclude that we have enough evidence to reject the null hypothesis, and we can said that at 5% of significance the proportion of students with jobs is significantly higher than 0.35.

Step-by-step explanation:

Data given and notation

n=83 represent the random sample taken

X=38 represent the students with jobs

[tex]\hat p=\frac{38}{83}=0.458[/tex] estimated proportion of students with jobs

[tex]p_o=0.35[/tex] is the value that we want to test

[tex]\alpha=0.05[/tex] represent the significance level

Confidence=95% or 0.95

z would represent the statistic (variable of interest)

[tex]p_v[/tex] represent the p value (variable of interest)  

Concepts and formulas to use  

We need to conduct a hypothesis in order to test the claim that the true proportion is higher than 0.35:  

Null hypothesis:[tex]p \leq 0.35[/tex]  

Alternative hypothesis:[tex]p > 0.35[/tex]  

When we conduct a proportion test we need to use the z statistic, and the is given by:  

[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)  

The One-Sample Proportion Test is used to assess whether a population proportion [tex]\hat p[/tex] is significantly different from a hypothesized value [tex]p_o[/tex].

Calculate the statistic  

Since we have all the info requires we can replace in formula (1) like this:  

[tex]z=\frac{0.458 -0.35}{\sqrt{\frac{0.35(1-0.35)}{83}}}=2.06[/tex]  

Statistical decision  

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.  

The significance level provided [tex]\alpha=0.05[/tex]. The next step would be calculate the p value for this test.  

Since is a right tailed test the p value would be:  

[tex]p_v =P(z>2.06)=0.020[/tex]  

So the p value obtained was a low value and using the significance level given [tex]\alpha=0.05[/tex] we have [tex]p_v<\alpha[/tex] so we can conclude that we have enough evidence to reject the null hypothesis, and we can said that at 5% of significance the proportion of students with jobs is significantly higher than 0.35.

According to the manufacturer of the candy Skittles, 20% of the candy produced are red. If we take a random sample of 100 bags of Skittles, what is the probability that the proportion in our sample of red candies will be less than 16%?

Answers

Answer:

0.15651

Step-by-step explanation:

This can be approximated using a Poisson distribution formula.

The Poisson distribution formula is given by

P(X = x) = (e^-λ)(λˣ)/x!

P(X ≤ x) = Σ (e^-λ)(λˣ)/x! (Summation From 0 to x)

where λ = mean of distribution = 20 red bags of skittles (20% of 100 bags of skittles means 20 red bags of skittles)

x = variable whose probability is required = less than 16 red bags of skittles

P(X < x) = Σ (e^-λ)(λˣ)/x! (Summation From 0 to (x-1))

P(X < 16) = Σ (e^-λ)(λˣ)/x! (Summation From x=0 to x=15)

P(X < 16) = P(X=0) + P(X=1) + P(X=2) +......+ P(X=15)

Solving this,

P(X < 16) = 0.15651

Final answer:

The question asks for the probability that the proportion of red Skittles is less than 16% from a sample of 100 bags. This involves the application of sampling distribution of a sample proportion, wherein the distribution should follow a normal distribution if certain conditions are met. The question can be solved by calculating a z-score and finding the corresponding probability from a standard normal distribution table.

Explanation:

This question involves the concept of sampling distribution of a sample proportion. Here, under certain conditions, the sampling distribution of p' (the sample proportion) tends to follow a normal distribution. The mean (expected value) of the distribution is equal to the population proportion (p), and the standard deviation (standard error) of the distribution is sqrt [ p(1 - p) / n ], where n is the size of the sample.

Given that the population proportion (p) = 0.20 and n = 100. We are asked to find the probability that the sample proportion (p') is less than 0.16 (16%). So, we can represent this situation as: P( p' < 0.16 ).

To find this probability we need to standardize our value of interest (0.16), resulting in a z-score. The z-score = ( p' - p ) / sqrt [ p(1 - p) / n ]. Plugging our values in, you can calculate the z-score, and apply it into a standard normal distribution table or use a calculator that can calculate probabilities using normal distribution to find the probability.

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If the probability of a student taking a calculus class is 0.10, the probability of taking a statistics class is 0.90, and the probability of taking a calculus class and a statistics class is 0.07, what is the probability of a student taking a calculus class or a statistics class

Answers

Final answer:

The probability of a student taking a calculus or a statistics class is found using the Addition Rule of Probability. For non-mutually exclusive events like these, the formula is P(A or B) = P(A) + P(B) - P(A and B). Substituting in the given values, we find the probability is 93%.

Explanation:

In probability theory, there's a rule called the Addition Rule of Probability. The rule states: the probability of the occurrence of either of two mutually exclusive events A and B is given by the sum of the probabilities of A and B.

However, if the two events aren't mutually exclusive (they can occur together), like our case here with the calculus and statistics classes, we need to adjust the formula. We subtract the probability of both of them happening. Hence, the formula becomes: P(A or B) = P(A) + P(B) - P(A and B).

If we plug in the given values: P(calculus or statistics) = P(calculus) + P(statistics) - P(calculus and statistics) = 0.10 + 0.90 - 0.07 = 0.93 or 93%.

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The probability that a student is taking either a calculus class or a statistics class is 0.93 or 93%. This uses the principle of inclusion-exclusion in probability.

To determine the probability of a student taking a calculus class or a statistics class, we use the principle of inclusion-exclusion for probabilities. This principle states:

P(A or B) = P(A) + P(B) - P(A and B)

Here, we are given the following probabilities:

Probability of taking calculus class, P(C) = 0.10Probability of taking statistics class, P(S) = 0.90Probability of taking both calculus and statistics classes, P(C and S) = 0.07

Using the inclusion-exclusion principle, we get:

P(C or S) = P(C) + P(S) - P(C and S)

= 0.10 + 0.90 - 0.07

= 0.93

Thus, the probability that a student is taking either a calculus class or a statistics class is 0.93 or 93%.

In San Francisco, 30% of workers take public transportation daily. In a sample of 10 workers, what is the probability that exactly three workers take public transportation daily?

Answers

Answer:

0.267

Step-by-step explanation:

p = 0.3 q = 0.7

10C3 × p³ × q⁷

0.266827932

Answer:

26.68% probability that exactly three workers take public transportation daily

Step-by-step explanation:

For each worker, there are only two possible outcomes. Either they take public transportation daily, or they do not. The probability of a worker taking public transportation daily is independent from other workers. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

30% of workers take public transportation daily.

This means that [tex]p = 0.3[/tex]

In a sample of 10 workers, what is the probability that exactly three workers take public transportation daily?

This is [tex]P(X = 3)[/tex] when [tex]n = 10[/tex]. So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 3) = C_{10,3}.(0.3)^{3}.(0.7)^{7} = 0.2668[/tex]

26.68% probability that exactly three workers take public transportation daily

Suppose that we have conducted a Simple Linear Regression for Exam 1 score by Homework 1 score and found the predicted line equation to be y_hat = 58.52 + 2.19x, where x represents Homework 1 score and y represents Exam 1 score. What Exam 1 score can a student who did not submit the homework expect to receive based on this predicted line equation? Group of answer choices y_hat 117.04 x 2.19 58.52

Answers

Answer:

58.52

Step-by-step explanation:

The predicted regression equation for predicting Exam 1 score is

y_hat=58.52+2.19x.

We have to find the predicted exam score 1 for student who did not submit homework. If the student did not submit homework 1 score then the homework 1 score will be zero. So,

y_hat=58.52+2.19(0)

y_hat=58.52.

Thus, the predicted exam score 1 for student who did not submit homework 1 score is 58.52.

(a) Estimate a second point on the tangent line. (t, p) = Correct: Your answer is correct. (b) Calculate the rate of change of the function at the labeled point. (Round your answer to one decimal place.) 12.5 Incorrect: Your answer is incorrect. thousand employees per year (c) Calculate the percentage rate of change of the function at the labeled point. (Round your answer to three decimal places.) 0.833 Incorrect: Your answer is incorrect. % per year

Answers

Complete Question

The complete question is shown on the first uploaded image

Answer:

a

The Estimated  second point is (t,p) =(5,9320)

b

The rate is 180 thousand employer per year

c

The percentage rate of change of the function is 1.939%

Step-by-step explanation:

Looking at the graph

  First is to obtain the scale of the graph what i mean is what the distance between each line segment

    Considering the y-axis  each line segment is

                              [tex]\frac{9300-9200}{5} = \frac{100}{5} =20[/tex]

So this means that after 9300 the next line segment is 9320

Considering the x-axis each line segment is

                            [tex]\frac{4-2}{4} = \frac{2}{4} = 0.5[/tex]

What this means is that 2 line segment after 4 is 4 +2 ×(0.5) =5

So looking this two points (new_t,new_p) = (5 , 9320) = we see that they form a coordinate

       B) The labeled point that we are to consider are

   [tex](t_1,p_2) = (4.8, 9284) \ (t_2,p_2) = (5, 9320)[/tex]

The rate change

                 [tex]= \frac{p_2-p_1}{t_2-t_1}=\frac{9320-9284}{5-4.8} = \frac{36}{0.2} = 180[/tex]

So the rate is 180 thousand employer per year

C)

 So to obtain the percentage rate of change of the function

   Now

       [tex]f(4.8) = 9284 \ Thousand[/tex]

      [tex]f'(4.8) = 180 \ Thousand[/tex]    

Note: This is so because differentiation is the same as  slope of the graph

    Hence the percentage  rate of change

                          [tex]\frac{f'(4.8)}{f(4.8)} *\frac{100}{1} = \frac{180 \ 000}{9284 \ 000} * \frac{100}{1}[/tex]

                           = 1.939%

Final answer:

The question seems to be related to calculus, discussing concepts of tangents and rates of change for a function. To find another point on a tangent line or calculate the rate of change, we need the function and additional details. The respective formulas for these calculations are mentioned, but we can't provide a factual answer without more information.

Explanation:

Given the question, it seems this is related to the field of calculus, specifically addressing concepts of tangents and rates of change of a function. However, to find another point on the tangent line or calculate the rate of change at a specific point, we need more context or the actual function.

Usually, for the first question, you can use the formula slope = (y2-y1) / (x2-x1), assuming (t, p) is a point on the tangent and you know the slope of the tangent. For the second question, the rate of change at a point is the derivative of the function at that point. For the third question, the percentage rate of change at a point is the derivative at that point divided by the function value at that point, multiplied by 100 to get percentage.

Without the function and some additional information, we cannot arrive at a factual answer. You might want to check the question again and include the necessary details.

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Suppose that L1 : V → W and L2 : W → Z arelinear transformations and E, F, and G are orderedbases for V, W, and Z, respectively. Show that, if Arepresents L1 relative to E and F and B representsL2 relative to F and G, then the matrix C = BA representsL2 ◦ L1: V → Z relative to E and G. Hint:Show that BA[v]E = [(L2 ◦ L1)(v)]G for all v ∈ V.

Answers

Answer:

a) v ∈ ker(L) if only if [tex][V]_{E}[/tex]N(A)

b) w ∈ L(v) if and only if [tex][W]_{F}[/tex] is in the column space of A

See attached

Step-by-step explanation:

See attached the proof Considering the vector spaces V and W with other bases E and F respectively.

Let L be the Linear transformation form V and W and A is the matrix representing L relative to E and F

Given that a 90% confidence interval for the mean height of all adult males in Idaho measured in inches was [62.532, 76.478]. Use this to answer all parts. What was the point estimate used to estimate the mean height of all adult males in Idaho?

Answers

Answer:

The point estimate used to estimate the mean height of all adult males in Idaho was 69.505 inches.

Step-by-step explanation:

The point estimate is the halfway point of the confidence interval, that is, the lower bound added to the upper bound, and then this sum is divided by 2. So

Lower bound: 62.535

Upper bound: 76.478

Point estimate:

[tex]P_{e} = \frac{62.535 + 76.478}{2} = 69.505[/tex]

The point estimate used to estimate the mean height of all adult males in Idaho was 69.505 inches.

The point estimate used to estimate the mean height of all adult males in Idaho was 69.505 inches.

Calculation of the estimation of the point

Since Given that a 90% confidence interval for the mean height of all adult males in Idaho measured in inches was [62.532, 76.478].

So, the estimation of the point is

[tex]= (62.532 + 76.478) \div 2[/tex]

= 69.505 inches

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An instructor gives her class a set of 10 problems with the information that the final exam will consist of a random selection of 5 of them. If a student has figured out how to do 7 of the problems, what is the probability that he or she will answer correctly (a) all 5 problems? (b) at least 4 of the problems?

Answers

Answer:

P

Step-by-step explanation:

(all 5 correctly) = (5 chosen among 7) / (5 chosen among 10)

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