Final answer:
The degrees of freedom for a chi-square test of independence with two variables each having three categories and a sample size of n = 75 is 4.
Explanation:
The question at hand involves determining the degrees of freedom (df) for a chi-square test of independence where two variables each have three categories, and the sample size is n = 75. To calculate the degrees of freedom for this scenario, you use the formula df = (r - 1)(c - 1) where r represents the number of rows (categories of one variable) and c represents the number of columns (categories of the other variable).
In this case, with both variables having three categories, we have r = 3 and c = 3, which gives us:
df = (3 - 1)(3 - 1) = (2)(2) = 4.
Therefore, the correct answer is a. 4 degrees of freedom for the chi-square distribution when testing for independence with a sample size of n = 75.
Here are summary statistics for randomly selected weights of newborn girls: n=235, x=30.5 hg, s=6.7 hg. Construct a confidence interval estimate of the mean. Use a 95% confidence level. Are these results very different from the confidence interval 28.9 hg< μ < 31.9 hg with only 12 sample values, x=30.4 hg, and s=2.3 hg?
What is the confidence interval for the population mean μ?
Answer:
a) The 95% confidence interval would be given by (29.639;31.361 )
And the results are not very different from 28.9 hg< μ < 31.9 hg
b)The 95% confidence interval would be given by (28.939;31.861)
And the results are not very different from 28.9 hg< μ < 31.9 hg
Step-by-step explanation:
1) Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
[tex]\bar X=30.5[/tex] represent the sample mean for the sample
[tex]\mu[/tex] population mean (variable of interest)
s=6.7 represent the sample standard deviation
n=235 represent the sample size
2) First confidence interval
The confidence interval for the mean is given by the following formula:
[tex]\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex] (1)
In order to calculate the critical value [tex]t_{\alpha/2}[/tex] we need to find first the degrees of freedom, given by:
[tex]df=n-1=235-1=234[/tex]
Since the Confidence is 0.95 or 95%, the value of [tex]\alpha=0.05[/tex] and [tex]\alpha/2 =0.025[/tex], and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,234)".And we see that [tex]t_{\alpha/2}=1.97[/tex]
Now we have everything in order to replace into formula (1):
[tex]30.5-1.97\frac{6.7}{\sqrt{235}}=29.639[/tex]
[tex]30.5+1.97\frac{6.7}{\sqrt{235}}=31.361[/tex]
So on this case the 95% confidence interval would be given by (29.639;31.361 )
And the results are not very different from 28.9 hg< μ < 31.9 hg
3) Second confidence interval
[tex]\bar X=30.4[/tex] represent the sample mean for the sample
[tex]\mu[/tex] population mean (variable of interest)
s=2.3 represent the sample standard deviation
n=12 represent the sample size
[tex]df=n-1=12-1=11[/tex]
Since the Confidence is 0.95 or 95%, the value of [tex]\alpha=0.05[/tex] and [tex]\alpha/2 =0.025[/tex], and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,11)".And we see that [tex]t_{\alpha/2}=2.20[/tex]
Now we have everything in order to replace into formula (1):
[tex]30.4-2.20\frac{2.3}{\sqrt{12}}=28.939[/tex]
[tex]30.4+2.20\frac{2.3}{\sqrt{12}}=31.861[/tex]
So on this case the 95% confidence interval would be given by (28.939;31.861)
And the results are not very different from 28.9 hg< μ < 31.9 hg
Can someone help me with this!
Answer:
Please read the answers below.
Step-by-step explanation:
Let's recall that in a square all its sides are equal length and all the four internal angles measure 90 °
5. If LN = 46, then we have:
OM = 46 (Same length than LN)
PN = LN/2 = 46/2 = 23
ON = √LN²/2 = √ 46²/2 = √ 2,116/2 = √ 1,058 = 32.53 (Rounding to two decimal places)
MN = ON = 32.53
6. m ∠EFG = 90°
m ∠GDH = ∠GDH/2 = 90/2 = 45°
m ∠FEG = ∠DEF/2 = 90/2 = 45°
m ∠DHG = 180 - (∠GDH + ∠DGH) = 180 - (45 + 45)= 180 - 90 = 90°
7. Solve for x
6x - 21 = ∠PQR/2
6x - 21 = 90/2
6x - 21 = 45
6x = 45 +21
6x = 66
x = 11
In a certain city, projections for the next year indicate there is a 20% chance that electronics jobs will increase by 1300, a 50% chance that they will increase by 300, and a 30% chance they will decrease by 900. Find the expected change in the number of electronics jobs in that city in the next year. The expected change is an increase of nothing jobs.
Answer:
110
Step-by-step explanation:
%20 increase = [tex]\frac{20}{100} 1300 = 260\\[/tex]
%50 decrease = [tex]\frac{50}{100}300 = 150[/tex]
%30 no change = [tex]\frac{30}{100}0 = 0[/tex]
Expected change = Increase - Decrease + No Change
Expected change = 260 - 150 + 0
Expected change = 110
In an advertisement, a pizza shop claims its mean delivery time is 30 minutes. A consumer group believes that the mean delivery time is greater than the pizza shop claims. A random sample of 41 delivery times has a mean of 31.5 minutes with standard deviation of 3.5 minutes. Does this indicate at a 5% significance level that the mean delivery time is longer than what the pizza shop claims?
Answer:
We conclude that at a 5% significance level that the mean delivery time is longer than what the pizza shop claims.
Step-by-step explanation:
We are given the following in the question:
Population mean, μ = 30 minutes
Sample mean, [tex]\bar{x}[/tex] = 31.5 minutes
Sample size, n = 41
Alpha, α = 0.05
Sample standard deviation, s = 3.5 minutes
First, we design the null and the alternate hypothesis
[tex]H_{0}: \mu = 30\text{ minutes}\\H_A: \mu > 30\text{ minutes}[/tex]
We use one-tailed z test to perform this hypothesis.
Formula:
[tex]z_{stat} = \displaystyle\frac{\bar{x} - \mu}{\frac{s}{\sqrt{n}} }[/tex]
Putting all the values, we have
[tex]z_{stat} = \displaystyle\frac{31.5 - 30}{\frac{3.5}{\sqrt{41}} } = 2.744[/tex]
Now, [tex]z_{critical} \text{ at 0.05 level of significance } = 1.64[/tex]
Since,
[tex]z_{stat} > z_{critical}[/tex]
We reject the null hypothesis and accept the alternate hypothesis.
Thus, we conclude that at a 5% significance level that the mean delivery time is longer than what the pizza shop claims.
Directions: Estimate the sum or difference using front end estimation.
1) 97 – 39
2) 812,344 – 187,675
3) 321 + 79
Directions: Estimate the product using front end estimation.
4) 315 x 821
5) 562 x 791
6) 82 x 156
7) 711 x 884
8) 126 x 952
9) 824 x 541
10) 4027 x 78
11) 796 x 123
Directions: Estimate the quotient using front end estimation.
12) 817 19
13) 3615 72
14) 232 64
15) 559 81
16) 2986 222
17) 10275 232
18) 7428 286
19) 7143 369
20) 628,597 1525
Answer:
Step-by-step explanation:
1) 1) 97 – 39. It becomes
100 - 40 = 60
2)2) 812,344 – 187,675. It becomes
800000 - 200000 = 600000
3)321 + 79. It becomes
300 + 80 = 410
4) 315 x 821. It becomes
300 + 800 = 1100
5) 562 x 791. It becomes
600× 800 = 480000
6) 82 x 156. It becomes
80×200 = 16000
7) 711 x 884. It becomes
700×900 = 630000
8) 126 x 952. It becomes
100×1000 = 100000
9) 824 x 541. It becomes
800× 500 = 400000
10) 4027 x 78. It becomes
4000×80 = 320000
11) 796 x 123. It becomes
800×100 = 80000
12) 817 19. It becomes
800/20 = 40
13) 3615 72. It becomes
4000/70 = 57.1 = 60
14) 232 64. It becomes
200/60 = 33.3 = 30
15) 559 81. It becomes
600/80 = 7.5 = 8
16) 2986 222. It becomes
3000/200 = 15
17) 10275 232. It becomes
10000/200 = 50
18) 7428 286. It becomes
7000/300 = 23.3 = 20
19) 7143 369. It becomes
7000/400 = 17.5 = 18
20) 628,597 1525, it becomes
600000 - 2000 = 300
Answer:
1) 100 - 40 = 60
2) 800000 - 200000 = 600000
3) 300 + 80 = 410
4) 3000 + 800 = 1100
5) 600× 800 = 480000
6) 80×200 = 16000
7) 700×900 = 630000
8) 100×1000 = 100000
9) 800× 500 = 400000
10) 4000×80 = 320000
11) 800×100 = 80000
12) 800/20 = 40
13) 4000/70 = 57.1 = 60
14) 200/60 = 33.3 = 30
15) 600/80 = 7.5 = 8
16) 3000/200 = 15
17) 10000/200 = 50
18) 7000/300 = 23.3 = 20
19) 7000/400 = 17.5 = 18
20) 600000 / 2000 = 300
Step-by-step explanation:
1) 1) 97 – 39. It becomes
100 - 40 = 60
2)2) 812,344 – 187,675. It becomes
800000 - 200000 = 600000
3)321 + 79. It becomes
300 + 80 = 410
4) 315 x 821. It becomes
300 + 800 = 1100
5) 562 x 791. It becomes
600× 800 = 480000
6) 82 x 156. It becomes
80×200 = 16000
7) 711 x 884. It becomes
700×900 = 630000
8) 126 x 952. It becomes
100×1000 = 100000
9) 824 x 541. It becomes
800× 500 = 400000
10) 4027 x 78. It becomes
4000×80 = 320000
11) 796 x 123. It becomes
800×100 = 80000
12) 817 19. It becomes
800/20 = 40
13) 3615 72. It becomes
4000/70 = 57.1 = 60
14) 232 64. It becomes
200/60 = 33.3 = 30
15) 559 81. It becomes
600/80 = 7.5 = 8
16) 2986 222. It becomes
3000/200 = 15
17) 10275 232. It becomes
10000/200 = 50
18) 7428 286. It becomes
7000/300 = 23.3 = 20
19) 7143 369. It becomes
7000/400 = 17.5 = 18
20) 628,597 1525, it becomes
600000 - 2000 = 300
Write and simplify the integral that gives the arc length of the following curve on the given interval b. If necessary, use technology to evaluate or approximate the integral. y:31n x, for 2sxs5 a. The integral that gives the arc length of the curve is L dx &The arc length of the curve is approximately (Round to three decimal places as needed.)
Answer:
a. [tex]\displaystyle AL = \int\limits^5_2 {\sqrt{1+ \frac{9}{x^2}} \, dx[/tex]
b. [tex]\displaystyle AL = 4.10322[/tex]
General Formulas and Concepts:
Calculus
Differentiation
DerivativesDerivative NotationDerivative Property [Multiplied Constant]: [tex]\displaystyle \frac{d}{dx} [cf(x)] = c \cdot f'(x)[/tex]
Integration
IntegralsDefinite IntegralsIntegration Constant CIntegration Property [Multiplied Constant]: [tex]\displaystyle \int {cf(x)} \, dx = c \int {f(x)} \, dx[/tex]
Integration Property [Addition/Subtraction]: [tex]\displaystyle \int {[f(x) \pm g(x)]} \, dx = \int {f(x)} \, dx \pm \int {g(x)} \, dx[/tex]
U-Substitution
Arc Length Formula [Rectangular]: [tex]\displaystyle AL = \int\limits^b_a {\sqrt{1+ [f'(x)]^2}} \, dx[/tex]
Step-by-step explanation:
Step 1: Define
Identify
y = 3ln(x)
Interval [2, 5]
Step 2: Find Arc Length
[Function] Differentiate [Logarithmic Differentiation]: [tex]\displaystyle \frac{dy}{dx} = \frac{3}{x}[/tex]Substitute in variables [Arc Length Formula - Rectangular]: [tex]\displaystyle AL = \int\limits^5_2 {\sqrt{1+ [\frac{3}{x}]^2}} \, dx[/tex][Integrand] Simplify: [tex]\displaystyle AL = \int\limits^5_2 {\sqrt{1+ \frac{9}{x^2}} \, dx[/tex][Integral] Evaluate: [tex]\displaystyle AL = 4.10322[/tex]Topic: AP Calculus AB/BC (Calculus I/I + II)
Unit: Applications of Integration
Book: College Calculus 10e
The arc length of the curve [tex]\( y = 3 \ln x \)[/tex] over the interval [2, 5] is approximately 12.092 units, obtained through numerical methods such as Simpson's rule or a CAS like Wolfram Alpha.
a. Writing and Simplifying the Integral:
The arc length L of the curve y = f(x) over the interval [a, b] is given by the following definite integral:
L = [tex]\int_a^b \sqrt{1 + \left( \dfrac{dy}{dx} \right)^2} dx[/tex]
First, find the derivative dy/dx of the given function:
y' = [tex]\dfrac{d}{dx} (3 \ln x) = \dfrac{3}{x}[/tex]
Now, plug f(x) = 3 \ln x and [tex]f'(x) = \dfrac{3}{x}[/tex] into the arc length formula for the interval [2, 5]:
L = [tex]\int_2^5 \sqrt{1 + \left( \dfrac{3}{x} \right)^2} dx[/tex]
L = [tex]\int_2^5 \sqrt{1 + \dfrac{9}{x^2}} dx[/tex]
b. Evaluating or Approximating the Integral:
This integral cannot be solved analytically using standard techniques. Therefore, we can use numerical methods like Simpson's rule or a CAS (Computer Algebra System) to approximate the value.
Using Simpson's rule with 10 subintervals, we get an approximate arc length of:
L ≈ 12.092
Alternatively, using a CAS like Wolfram Alpha, we can obtain a more precise numerical value:
L ≈ 12.091971077
Therefore, the arc length of the curve is approximately 12.092 units.
In a survey, 31% of a randomly selected sample of n = 935 American adults said that they do not get enough sleep each night. The margin of error for the 95% confidence level was reported to be 3.2%. (a) Use the survey information to create a 95% confidence interval for the percentage that feels they don't get enough sleep every night_________%.(b) Do you think this sample could be used to estimate the percentage of college students who think they don't get enough sleep each night? Why or why not? A. Yes, the population the sample comes from is representative of college students, fulfilling the Fundamental Rule for Using Data For Inference B. No, the population the sample comes from may not be representative of college students, violating the Fundamental Rule for Using Data For Inference. O C. Yes, the population the sample comes from is representative of college students, violating the Fundamental Rule for Using Data For Inference. D. No, the population the sample comes from may not be representative of college students, fulfilling the Fundamental Rule for Using Data For Inference
Answer:
a) [0.278; 0.342]
b) No, the population the sample comes from may not be representative of college students, violating the Fundamental Rule for Using Data For Inference.
Step-by-step explanation:
Hello!
a)
The study variable is
X: Number of American adults that said that they do not get enough sleep each night.
The sample is n= 935 American Adults
Sample proportion 'p= 0.31
The margin of error of the 95% CI d= 0.032
The formula for a CI for the population proportion is:
['p ± [tex]Z_{1-\alpha /2}[/tex]*[tex]\sqrt{\frac{'p(1-'p)}{n} }[/tex]]
The basic structure of the CI formula is "Point estimator" ± "Margin of error"
So with the given data, you can calculate the CI.
[0.31 ± 0.032]
[0.278; 0.342]
So with a confidence level of 95%, you'd expect that the interval [0.278; 0.342] will contain the population proportion of the American adults that don't get enough sleep at night.
b)
The answer is no. The sample is of "American adults" there is no information on their education level, therefore it is possible that all of them have a college education or that none of the have. Since no further information about their education then you cannot be certain that this sample will be representative of the American College Students.
Then the correct option is B
I hope you have a SUPER day!
A certain pen has been designed so that true average writing lifetime under controlled conditions (involving the use of awriting machine) is at least 10 hours. A random sample of 18 pens is selected, the writing lifetime of each is determined,and a normal probability plot of the resulting data supports the use of a one-sample t test.a. What hypotheses should be tested if the investigators believe a priori that the design specification has been satisfied?b. What conclusion is appropriate if the hypotheses of part (a) are tested,t = —23, and a = .05?c. What conclusion is appropriate if the hypotheses of part (a) are tested, t = —1.8, and u = .01?d. What should be concluded if the hypotheses of part (a) are tested and t = —3.6 ?
Answer:
a) Null hypothesis:[tex]\mu \geq 10[/tex]
Alternative hypothesis:[tex]\mu < 10[/tex]
b) [tex]p_v =P(t_{17}<-2.3)=0.017[/tex]
And on this case since the p value is lower than the significance level we have enough evidence to reject the null hypothesis.
c) [tex]p_v =P(t_{17}<-1.8)=0.0448[/tex]
And on this case since the p value is higher than the significance level we have enough evidence to FAIL to reject the null hypothesis.
d) [tex]p_v =P(t_{17}<-3.6)=0.0011[/tex]
And on this case since the p value is lower than the significance level we have enough evidence to reject the null hypothesis.
Step-by-step explanation:
1) Data given and notation
[tex]\bar X[/tex] represent the sample mean
[tex]s[/tex] represent the sample deviation
[tex]n=18[/tex] sample size
[tex]\mu_o =10[/tex] represent the value that we want to test
[tex]\alpha[/tex] represent the significance level for the hypothesis test.
t would represent the statistic (variable of interest)
[tex]p_v[/tex] represent the p value for the test (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the true mean is at least 10 hours, the system of hypothesis would be:
Part a
Null hypothesis:[tex]\mu \geq 10[/tex]
Alternative hypothesis:[tex]\mu < 10[/tex]
If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:
[tex]t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}[/tex] (1)
Part b
For this case we have t=-2.3 , [tex]\alpha=0.05[/tex]
First we need to find the degrees of freedom [tex]df=n-1=18-1=17[/tex]
Now since we are conducting a left tailed test the p value is given by:
[tex]p_v =P(t_{17}<-2.3)=0.017[/tex]
And on this case since the p value is lower than the significance level we have enough evidence to reject the null hypothesis.
Part c
For this case we have t=-1.8 , [tex]\alpha=0.01[/tex]
First we need to find the degrees of freedom [tex]df=n-1=18-1=17[/tex]
Now since we are conducting a left tailed test the p value is given by:
[tex]p_v =P(t_{17}<-1.8)=0.0448[/tex]
And on this case since the p value is higher than the significance level we have enough evidence to FAIL to reject the null hypothesis.
Part d
For this case we have t=-3.6 , [tex]\alpha=0.05[/tex]
First we need to find the degrees of freedom [tex]df=n-1=18-1=17[/tex]
Now since we are conducting a left tailed test the p value is given by:
[tex]p_v =P(t_{17}<-3.6)=0.0011[/tex]
And on this case since the p value is lower than the significance level we have enough evidence to reject the null hypothesis.
The student is learning about conducting a one-sample t-test in a hypothesis testing problem related to the lifetime of a pen. The null and alternative hypothesis are defined, and conclusions are drawn based on various test statistics and significance levels.
Explanation:This situation relates to hypothesis testing in statistics, in particular the usage of a one-sample t-test.
The null hypothesis (H0) and alternative hypothesis (Ha) to be tested would be:
H0: μ ≥ 10 hours (The average lifetime of the pen is at least 10 hours)Ha: μ < 10 hours (The average lifetime of the pen is less than 10 hours)The t value represents the test statistic for conducting the hypothesis test, and the 'α' and 'u' are the significance levels.
With t = -23 and α = 0.05, this falls within the rejection region, as the t value is less than the critical value for a one-tailed test at significance level α = 0.05. Hence, we reject the null hypothesis. There is evidence to suggest that the pen's lifetime is less than 10 hours.
Similarly, with t = -1.8 and u = 0.01, the null hypothesis would be retained, as this value is within the acceptance region.The conclusion would be that there is not sufficient evidence to suggest that the pen's lifetime is less than 10 hours.
Finally, with t = -3.6, the null hypothesis is rejected, suggesting that the pen's lifetime is less than 10 hours. However, this is only applicable if the significance level is above the calculated p-value for t = -3.6.
Learn more about Hypothesis Testing here:https://brainly.com/question/34171008
#SPJ3
Our environment is very sensitive to the amount of ozone in the upper atmosphere. The level of ozone normally found is 7.5 parts/million (ppm). A researcher believes that the current ozone level is not at a normal level. The mean of 16 samples is 7.8 ppm with a standard deviation of 0.8. Assume the population is normally distributed. A level of significance of 0.01 will be used. Make the decision to reject or fail to reject the null hypothesis.
Answer:
We accept H₀ with the information we have, we can say level of ozone is under the major limit
Step-by-step explanation:
Normal Distribution
population mean = μ₀ = 7.5 ppm
Sample size n = 16 df = n - 1 df = 15
Sample mean = μ = 7.8 ppm
Sample standard deviation = s = 0.8
We want to find out if ozono level, is above normal level that is bigger than 7.5
1.- Hypothesis Test
null hypothesis H₀ μ₀ = 7.5
alternative hypothesis Hₐ μ₀ > 7.5
2.-Significance level α = 0.01 we will develop one tail-test (right)
then for df = 15 and α = 0,01 from t -student table we get
t(c) = 2.624
3.-Compute t(s)
t(s) = ( μ - μ₀ ) / s /√n ⇒ t(s) = ( 7.8 - 7.5 )*4/0.8
t(s) = 0.3*4/0.8
t(s) = 1.5
4.-Compare t(s) and t(c)
t(s) < t(c) 1.5 < 2.64
Then t(s) is inside the acceptance region. We accept H₀
Given is a finite set of spherical planets, all of the same radius and no two intersecting. On the surface of each planet consider the set of points not visible from any other planet. Prove that the total area of these sets is equal to the surface area of one planet.
Answer:
Step-by-step explanation:
To answer this question, First, we define a direction in space, which defines
the North Pole of each planet.
We also assume that the direction is not at 90° perpendicular to the axis of any two planet.
Assume we now define an order on the set of planet by saying that planet A ≥ B, when removing all the other planet from space, the north pole B, is visible from A.
If we refer to the direction of the planet in the diagram, we discover that,
1, A ≥ A
2, If A ≥ B and B≥ A,
Then A = B
3, If A ≥ B, and B ≥ C , then A ≥ C
4, Either A ≥ B or B ≥ A
It should also be noted that the array of order above has a unique maximal element (M). This is the only planet whose North Pole is not visible from another.
If we now consider a sphere of the same radius as the planets. Remove
from it all North Poles defined by directions that are perpendicular
to the axis of two of the planets. This is a set of area zero.
For every other point on this sphere, there exists a direction in
space that makes it the North Pole, and for that direction, there
exists a unique North Pole on one of the planets which is not visible
from the others. Hence the total area of invisible points is equal
to the area of this sphere, which in turn is the area of one of the planets.
The Department of Education would like to test the hypothesis that the average debt load of graduating students with a Bachelor's degree is equal to $17,000. A random sample of 34 students had an average debt load of $18,200. It is believed that the population standard deviation for student debt load is $4,200. The Department of Education would like to set α = 0.05. Which one of the following statements is true?
Because the p-value is greater than α, we fail to reject the null hypothesis and conclude that the average debt load is equal to $17,000.
Because the p-value is less than α, we reject the null hypothesis and conclude that the average debt load is equal to $17,000.
Because the p-value is less than α, we fail to reject the null hypothesis and conclude that the average debt load is not equal to $17,000.
Because the p-value is greater than α, we fail to reject the null hypothesis and cannot conclude that the average debt load is not equal to $17,000.
To test the hypothesis that the average debt load of graduating students with a Bachelor's degree is equal to $17,000, a hypothesis test needs to be conducted using the given sample data. The p-value needs to be calculated and compared to the significance level α to determine the conclusion. Without the p-value, we cannot make a definitive conclusion.
Explanation:To test the hypothesis that the average debt load of graduating students with a Bachelor's degree is equal to $17,000, the Department of Education would conduct a hypothesis test using the given sample data. The null hypothesis, denoted as H0, states that the average debt load is equal to $17,000, while the alternative hypothesis, denoted as Ha, states that the average debt load is not equal to $17,000.
Based on the given information, the sample mean debt load is $18,200, the population standard deviation is $4,200, and the sample size is 34. Using these values, we can calculate the p-value, which represents the probability of obtaining a sample mean as extreme as $18,200 or more extreme, assuming the null hypothesis is true. The p-value is the probability of observing a sample mean of $18,200 or more extreme, given that the average debt load is $17,000.
To determine the conclusion of the hypothesis test, we compare the p-value to the significance level α. In this case, the given α is 0.05. If the p-value is less than α, we reject the null hypothesis and conclude that the average debt load is not equal to $17,000. If the p-value is greater than or equal to α, we fail to reject the null hypothesis and cannot conclude that the average debt load is not equal to $17,000.
In this scenario, the p-value is not given, so we cannot make a definitive conclusion. We would need to calculate the p-value based on the given information to determine which statement is true.
Learn more about Hypothesis testing here:https://brainly.com/question/34171008
#SPJ3
The correct option is A. [tex]\text{Because the p-value is greater than}[/tex] [tex]\alpha,[/tex] [tex]\text{ we fail to reject the null hypothesis and conclude that the average debt load is equal to }[/tex] [tex]\$17,000.[/tex]
To determine the correct statement based on the hypothesis test conducted:
Given data:
Population standard deviation[tex](\( \sigma \)): \$4,200[/tex]
Sample size [tex](\( n \)): 34[/tex]
Sample mean [tex](\( \bar{x} \)): \$18,200[/tex]
Hypothesized population mean [tex](\( \mu_0 \))[/tex]: [tex]\$17,000.[/tex]
Significance level [tex](\alpha): 0.05[/tex]
Hypotheses
We are testing whether the average debt load [tex](\( \mu \))[/tex] of graduating students with a Bachelor's degree is equal to [tex]\$17,000.[/tex]
Null hypothesis [tex](\( H_0 \)): \( \mu = 17,000 \)[/tex]
Alternative hypothesis [tex](\( H_1 \)): \( \mu \neq 17,000 \)[/tex]
This is a two-tailed test because [tex]\( H_1 \)[/tex] states that [tex]\( \mu \)[/tex] is not equal to [tex]\$17,000.[/tex]
Test Statistic
Since the population standard deviation [tex](\( \sigma \))[/tex] is known and the sample size [tex](\( n \))[/tex] is greater than [tex]30[/tex], we use a z-test.
The test statistic [tex]\( z \)[/tex] is calculated as:
[tex]\[ z = \frac{\bar{x} - \mu_0}{\frac{\sigma}{\sqrt{n}}} \][/tex]
Calculate [tex]\( z \)[/tex]
[tex]\[ z = \frac{18,200 - 17,000}{\frac{4,200}{\sqrt{34}}} \][/tex]
[tex]\[ z = \frac{1,200}{\frac{4,200}{5.83}} \][/tex]
[tex]\[ z = \frac{1,200 \times 5.83}{4,200} \][/tex]
[tex]\[ z = 1.66 \][/tex]
P-Value Calculation
The p-value is the probability of observing a sample mean at least as extreme as [tex]18,200[/tex] if the null hypothesis [tex](\( \mu = 17,000 \))[/tex] is true. Since this is a two-tailed test, we consider both tails of the normal distribution.
From the standard normal distribution table:
The area to the right of [tex]\( z = 1.66 \)[/tex] (since [tex]\( z \)[/tex] is positive) is approximately [tex]0.0485.[/tex]
Therefore, the p-value for the two-tailed test is approximately [tex]\( 2 \times 0.0485 = 0.097 \).[/tex]
Conclusion
Compare the p-value [tex](0.097)[/tex] with the significance level [tex]\alpha = 0.05)\( \text{p-value} (0.097) > \alpha (0.05) \)[/tex]
Since the p-value is greater than the significance level ([tex]\alpha[/tex]), we fail to reject the null hypothesis [tex]\( H_0 \)[/tex]. This means we do not have enough evidence to conclude that the average debt load is different from [tex]\$17,000.[/tex]
20)
The projected value of an investment is modeled by the exponential function V(t) = 30,000(1.125) where V(t) is the total value
after t years. What does 1.125 represent in the function?
The growth factor of the investment
The initial value of the investment
The projected value of the investment
D)
The value of the investment after t years:
The 1.125 in the exponential function V(t) = 30,000(1.125)^t represents the growth factor of the investment, indicating an annual growth of 12.5%.
Explanation:In the exponential function V(t) = 30,000(1.125)^t, the 1.125 represents the growth factor of the investment. This means each year, the value of the investment grows by 12.5%. It's the rate at which the initial value of the investment, 30,000 in this case, increases on an annual basis. Therefore, the exponential function shows us how the value of the investment changes over time with this constant growth factored in.
Learn more about growth factor here:https://brainly.com/question/12052909
#SPJ12
when a tow truck is called, the cost of the service is given by the linear function y = 3x +75, when y is in dollars and x is the number of miles the car is towed. Find and interpret the slope and y intercept of the linear equation.
Answer:
Slope: 3
Y intercept: y = 75
Step-by-step explanation:
The slope of a linear function is the coefficient in front of x. In this case, 3 is being multiplied by x, indicating the slope is 3.
The y-intercept is the y value where the graph of the function crosses the y-axis. In other words, it's the y value when x = 0. To find the y-intercept, simply substitute 0 for x:
[tex]y = 3(0) + 75 \\ y = 75[/tex]
We find that the y-intercept is y = 75.
In the linear function y=3x+75, the slope 3 represents the rate of cost per mile to tow a car ($3/mile), and the y-intercept 75 is the basic fee for the towing service. So, the total cost is a fixed fee of $75 plus $3 per mile towed.
Explanation:In the linear function y = 3x + 75, the slope, represented by '3', is the cost in dollars per mile to tow a car. This means for each mile the car is towed, the cost increases by $3.
The y-intercept, represented by '75', is the basic fee for the service, or the cost in dollars that one must pay even if the car isn't towed any miles.
So, to interpret the equation function: the total cost (y) of having a car towed is composed of a fixed fee of $75 plus an additional $3 for each mile (x) the car is towed.
Learn more about Linear Functions here:https://brainly.com/question/31353350
#SPJ11
What is the recommended frequency for updating lean budget distribution?
Answer:
On demand
Step-by-step explanation:
On demand (fund Value Streams, not projects).
Lean Budgets is a collection of methods that significantly reduce overhead by financing and encouraging Value Streams instead of projects while preserving financial and user-fit governance. This is done by comprehensive work program assessment, active management of Epic finances, and complex budget changes.
Hence, the recommended frequency for updating lean budget distribution on demand that is fund value streams.
Lean budget distribution should be updated at least once per quarter, or as often as required by the specific circumstances of your organization. The goal of a lean budget is to optimize resource use and reduce waste to deliver more value to customers.
Explanation:The recommended frequency for updating lean budget distribution is not fixed and largely depends on the specific needs, context, and circumstances of your organization. However, a common practice is to review and adjust the lean budget allocation at least once per quarter. This allows you to take into account any changes in strategy, project progress, and business environment. It's important to highlight that these revisions should be strategic and informed by data and not just random shifts in resource allocation. Remember, the main goal of a lean budget is to minimize waste and optimize resource utilization to bring more value to customers.
Learn more about Lean Budget Distribution here:https://brainly.com/question/14314990
#SPJ6
The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minute. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes.
a. .0500 b. .0228 c. .0456 d. .0250
Answer:
The correct option is B) 0.0228
Step-by-step explanation:
Consider the provided information.
The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minute.
Thus, the value of n = 100, [tex]\bar x=3.1[/tex] and σ = 0.5
We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes.
The null and alternative hypotheses are,
[tex]H_0:\mu\leq3[/tex] and [tex]H_a:\mu>3[/tex]
Compute the test statistic [tex]z=\frac{\bar x-\mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]z=\frac{3.1-3}{\frac{0.5}{\sqrt{100}}}[/tex]
[tex]z=\frac{0.1}{0.05}[/tex]
[tex]z=2[/tex]
By using the table.
P value = P(Z>2) = 0.0228
Hence, the correct option is B) 0.0228
If other factors are held constant, what happens to a confidence interval if the sample variance increases? The range of t scores increases and the width of the interval increases. The range of t scores decreases and the width of the interval decreases. The standard error increases and the width of the interval increases. The standard error decreases and the width of the interval decreases.
Answer:
The standard error increases and the width of the interval increases
Step-by-step explanation:
The variance is equal to the square of the standard deviation. An increase in variance will increase the standard deviation.
The width of the confidence interval can be defined as:
[tex]W=UL-LL=2z\sigma/\sqrt{n}[/tex]
The width is proportional to the standard deviation, so when the variance increases, the standard deviation and also the width of the interval increases.
The GT brewery has hired you as an analyst to understand its market position. It is particularly concerned about its major competitor, the ML Brewery, and which brewery has the ‘lead’ market share. Recent history has suggested that which brewery has the ‘lead market share’ can be modeled as a Markov Chain using three states: GT, ML, and Other Company (OC). Data on the lead market share is taken monthly and you have constructed the following one-step transition probability matrix from past data:
GT ML OC
GT 0.75 0.15 0.10
ML 0.30 0.60 0.10
OC 0.20 0.10 0.70
a. The current state of the lead market share in November is GT·The GT Brewery is considering launching a new brand in March only if it has the lead market share in February. Determine the probability that GT Brewery will launch this new brand. Please show any equations or matrices used to calculate this probability and briefly explain how you obtained your answer.
b. Provide the steady-state equations and calculate the steady-state probabilities for the Markov Chain.
Answer
The answer and procedures of the exercise are attached in the following archives.
Step-by-step explanation:
You will find the procedures, formulas or necessary explanations in the archive attached below. If you have any question ask and I will aclare your doubts kindly.
A recent report states the variance of the fuel consumption of a certain car is equal to 16.81 miles per gallon (mpg). A researcher claims the actual variance is lower. A sample of 21 cars produced a variance of 6.25 mpg. Test the claim at alpha = 0.05, use the P-value method. For question #29, tell what type of test his is (right, left, or two-tailed). For question #30, select from choices given with regard to identifying the alternate hypothesis. For question #31, fill in the blank with your Critical Value(s) for Chi-square. For question #32, fill in the space provided with your calculated value of Chi-square. For question #33, use your answer from #32 to select between which two areas your P-value lies. For question #34, based on your answer for #33, answer True or False as to whether the null hypothesis will be rejected.
Answer:
H0: [tex]\sigma \geq 4.1[/tex]
H1: [tex]\sigma <4.1[/tex]
[tex]\Chi^2_{crit} =10.851[/tex]
[tex] t=(21-1) [\frac{2.5}{4.1}]^2 =7.436[/tex]
[tex]p_v = P(\Chi^2_{20}<7.436)=0.0050[/tex]
True, since our p value is lower than the significance level we have enough evidence to reject the null hypothesis at 5% of significance. And we can conclude that the population standard dviation is less than 4.1 (Or the variance is less than 16.81)
Step-by-step explanation:
Previous concepts and notation
The chi-square test is used to check if the standard deviation of a population is equal to a specified value. We can conduct the test "two-sided test or a one-sided test".
[tex]\bar X [/tex] represent the sample mean
n = 21 sample size
[tex]s^2 =6.25[/tex] represent the sample variance
[tex]s=2.5[/tex] represent the sample deviation
[tex]\sigma^2_0 =16.81[/tex] represent the target variance
[tex]\sigma_o =4.1[/tex] the value that we want to test
[tex]p_v [/tex] represent the p value for the test
t represent the statistic
[tex]\alpha=0.05[/tex] significance level
State the null and alternative hypothesis
On this case we want to check if the population variance is lower (or if the deviation is lower than 4.1) than 16.81, so the system of hypothesis are:
H0: [tex]\sigma \geq 4.1[/tex]
H1: [tex]\sigma <4.1[/tex]
In order to check the hypothesis we need to calculate th statistic given by the following formula:
[tex] t=(n-1) [\frac{s}{\sigma_o}]^2 [/tex]
This statistic have a Chi Square distribution distribution with n-1 degrees of freedom.
What is the critical value for the test statistic at an α = 0.05 significance level?
Since is a left tailed test the critical zone it's on the left tail of the distribution. On this case we need a quantile on the chi square distribution with 20 degrees of freedom that accumulates 0.05 of the area on the left tail and 0.95 on the right tail.
We can calculate the critical value in excel with the following code: "=CHISQ.INV(0.05,20)". And our critical value would be [tex]\Chi^2_{crit} =10.851[/tex]
What is the value of your test statistic?
Now we have everything to replace into the formula for the statistic and we got:
[tex] t=(21-1) [\frac{2.5}{4.1}]^2 =7.436[/tex]
What is the approximate p-value of the test?
For this case since we have a left tailed test the p value is given by:
[tex]p_v = P(\Chi^2_{20}<7.436)=0.0050[/tex]
Based on your answer for the p value, answer True or False as to whether the null hypothesis will be rejected.
True, since our p value is lower than the significance level we have enough evidence to reject the null hypothesis at 5% of significance. And we can conclude that the population standard dviation is less than 4.1 (Or the variance is less than 16.81)
A production manager at a wall clock company wants to test their new wall clocks. The designer claims they have a mean life of 16 years with a standard deviation of 4 years. If the claim is true, in a sample of 42 wall clocks, what is the probability that the mean clock life would be greater than 15.1 years? Round your answer to four decimal places.
Answer:
92.79% probability that the mean clock life would be greater than 15.1 years.
Step-by-step explanation:
The Central Limit Theorem estabilishes that, for a random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], a large sample size can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]\frac{\sigma}{\sqrt{n}}[/tex].
Normal probability distribution
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
[tex]\mu = 16, \sigma = 4, n = 42, s = \frac{4}{\sqrt{42}} = 0.6172[/tex]
What is the probability that the mean clock life would be greater than 15.1 years?
This probability is 1 subtracted by the pvalue of Z when [tex]X = 15.1[/tex]. So:
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{15.1 - 16}{0.6172}[/tex]
[tex]Z = -1.46[/tex]
[tex]Z = -1.46[/tex] has a pvalue of 0.0721.
So there is a 1-0.0721 = 0.9279 = 92.79% probability that the mean clock life would be greater than 15.1 years.
Final answer:
Using the Central Limit Theorem and the given standard deviation and mean, the standard error was calculated, and then the z-score was determined. After finding the z-score, the area to the right of it on the standard normal distribution curve gives the probability that the mean clock life is greater than 15.1 years, which is 0.9274.
Explanation:
To find the probability that the mean clock life of a sample of 42 wall clocks is greater than 15.1 years, we can use the Central Limit Theorem which tells us that the sampling distribution of the sample mean will be normally distributed if the sample size is large enough. Since we are dealing with a sample of 42, which is generally considered sufficiently large, the sampling distribution of the sample mean is normally distributed. Given the population mean (μ) is 16 years, the standard deviation (σ) is 4 years, the sample size (n) is 42, and we want to find the probability of the sample mean (μ_x) > 15.1 years, we first need to find the standard error (SE) which is σ/sqrt(n). Then we can find the z-score which is (15.1 - μ) / SE. Lastly, we use the z-score to find the probability from z-tables or a calculator with normal distribution functions.
The standard error (SE) is:
SE = 4 / sqrt(42) ≈ 0.6172
The z-score (z) is:
z = (15.1 - 16) / 0.6172 ≈ -1.4573
To find the probability of the sample mean being greater than 15.1 years, we want the area to the right of the z-score on the standard normal distribution curve. Looking up the z-score of -1.4573 on the z-table or using a normal distribution calculator gives us the probability to the left of the z-score. We subtract this value from 1 to find the probability to the right:
P(X > 15.1) = 1 - P(Z < -1.4573) ≈ 1 - 0.0726 = 0.9274
Therefore, the probability that the mean clock life is greater than 15.1 years is 0.9274 when rounded to four decimal places.
A manufacturer of cereal has a machine that, when working properly, puts 20 ounces of cereal on average into a box with a standard deviation of 1 ounce. Every morning workers weigh 25 filled boxes. If the average weight is off by more than 1 percent from the desired 20 ounces per box, company policy requires them to recalibrate the machine. In a sample of 100 days where the machine is working properly all day, on how many of the days is it expected the machine will be recalibrated?
Answer:
Step-by-step explanation:
Given
mean [tex]\mu =20\ ounces[/tex]
standard deviation [tex]\sigma =1\ ounce[/tex]
The no of sample boxes weigh Every morning is 25
Average weight is 1 % more than average
i.e. [tex]20+20\times 0.1=20.2 ounce[/tex]
The company re-calibrates the machine
[tex]P\left ( \bar{x}> 20.2\right )=P\left ( z-\frac{20.2-20}{\frac{1}{\sqrt{25}}}\right )[/tex]
[tex]=P\left ( z> 1\right )=1-P\left ( z\leq 1\right )[/tex]
[tex]=1-0.8413[/tex]
[tex]=0.1587[/tex]
Therefore the Probability that the average weight of box is more than 20.2 ounce is 0.1587
No of days the machine is expected to re-calibrate is [tex]100\times 0.1587=16\ days[/tex]
find an equation of the line satisfying the given conditions. write the equation using function notation. Through (-20,5) and (-36, 9) And can you show me the steps?
Answer:
The equation of the line using function notation is
[tex]y=f(x)=-\frac{1}{4}x[/tex]
Step-by-step explanation:
Given points are (-20,5) and (-36, 9)
Now to find the equation of the line passes through these points
Let [tex](x_{1},y_{1})[/tex] and [tex](x_{2},y_{2})[/tex] be the two given points (-20,5) and (-36, 9) respectively.
To find slope
[tex]m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}[/tex]
[tex]m=\frac{9-5}{-36-(-20)}[/tex]
[tex]m=\frac{4}{-36+20}[/tex]
[tex]m=\frac{4}{-16}[/tex]
[tex]m=-\frac{1}{4}[/tex]
Therefore [tex]m=-\frac{1}{4}[/tex]
The equation of the line is of thr form y=mx+c
The point (-20,5) passes through the above line and [tex]m=-\frac{1}{4}[/tex]
[tex]5=-\frac{1}{4}(-20)+c[/tex]
[tex]5=5+c[/tex]
[tex]c=0[/tex]
[tex]y=-\frac{1}{4}x+0[/tex]
Therefore [tex]y=-\frac{1}{4}x[/tex]
Therefore the equation of the line using function notation is
[tex]y=f(x)=-\frac{1}{4}x[/tex]
Find equations of both the tangent lines to the ellipse x2 + 9y2 = 81 that pass through the point (27, 3). y = (smaller slope) y = (larger slope)
Answer:
The tangent line equations are:
- The one that has the smaller slope [tex]\bold{y =3}[/tex]
- The one that has the larger slope [tex]\bold{y = \cfrac 14 x - \cfrac{15}{4}}[/tex]
Step-by-step explanation:
In order to find the tangent lines we need to find first the first derivative since the first derivative evaluated at a point give us the slope of the tangent line.
Working with implicit differentiation.
In order to find the derivative we can work with implicit differentiation and we get
[tex]2x+18y \cfrac{dy}{dx}= 0[/tex]
Notice that only when we are finding the derivative of an expression that has y we multiply by dy/dx due chain rule.
Solving for the first derivative we get
[tex]18y\cfrac{dy}{dx}=-2x[/tex]
[tex]\cfrac{dy}{dx}=-\cfrac{x}{9y}[/tex]
So the equation of the first derivative at the point (x,y) give us the first equation for the slope.
[tex]m=-\cfrac{x}{9y}[/tex]
Slope of a line using definition.
We can also find the slope of the line that will pass the point (x,y) trough the point (27,3) using the definition:
[tex]m = \cfrac{y_2-y_1}{x_2-x_1}[/tex]
Replacing the point we get
[tex]m=\cfrac{y-3}{x-27}[/tex]
That is another equation for the slope.
Finding the value of the slopes.
We can now set both slope equations equal to each other to find the point (x,y) where they intersect and the value of the slopes.
[tex]-\cfrac{x}{9y}= \cfrac{y-3}{x-27}[/tex]
We can work with cross multiplication to get
[tex]-x(x-27)=9y(y-3)[/tex]
And we can distribute and simplify
[tex]-x^2+27x=9y^2-27y[/tex]
Moving everything to the right side
[tex]0=x^2-27x+9y^2-27y\\\\0=x^2+9y^2-27x-27y[/tex]
At this point we can use the ellipse equation so we can replace [tex]x^2+9y^2[/tex] with 81, that will give us
[tex]0=81-27x-27y[/tex]
Then we can divide by 27 and solve for y.
[tex]0=3-x-y\\y= 3-x[/tex]
At this point we can replace on the ellipse equation.
[tex]x^2+9(3-x)^2=81[/tex]
And we can distribute and simplify.
[tex]x^2+9(9-6x+x^2)=81\\x^2+81-54x+9x^2=81\\x^2-54x+9x^2=0\\10x^2-54x=0\\[/tex]
So then we can factor and solve for x.
[tex]2x(5x-27)=0[/tex]
Setting each factor and solve for x we get
[tex]x= 0, \cfrac{27}{5}[/tex]
At x = 0, we can find the y value.
[tex]y= 3-x\\y= 3-0\\y= 3[/tex]
And the slope
[tex]m = -\cfrac{x}{9y}\\m = -\cfrac{0}{9y}\\m = 0[/tex]
So the line equation is
[tex]y-3=0(x-0)\\y=3[/tex]
For the second point x = 27/5 we have:
[tex]y= 3-\cfrac{27}{5}\\y=-\cfrac{12}{5}[/tex]
So slope is:
[tex]m = -\cfrac{\cfrac{27}{5}}{9\left(-\cfrac{12}{5}\right)}[/tex]
[tex]m = \cfrac 14[/tex]
So the line equation is
[tex]y-\left(-\cfrac{12}{5}\right)= \cfrac 14 \left(x -\cfrac{27}{5}\right)\\y = \cfrac 14 x - \cfrac{15}{4}[/tex]
Thus the equations of tangent lines are:
[tex]\bold{y =3}[/tex]
and
[tex]\bold{y = \cfrac 14 x - \cfrac{15}{4}}[/tex]
To find the equations of the tangent lines to the ellipse that passes through a specific point, differentiate the equation of the ellipse to get a formula for the slope at any point on the ellipse. Set this equal to the slope of the line from the point on the ellipse to the specific point, and solve. The resultant solutions give the points of tangency, and the lines through these points and the specific point are the desired tangent lines.
Explanation:The subject of the question is about finding the equations of the tangent lines to the ellipse x^2 + 9y^2 = 81 that pass through a specific point (27, 3). We first differentiate the equation of the ellipse to get a general formula for the slope of the tangent line at any point on the ellipse. The differentiation of x^2 + 9y^2 = 81 with respect to x gives 2x + 18yy' = 0, so y' = -x/ (9y). Now, we put the slopes y' equal to the slopes of line from (x, y) to (27, 3), and solve the resulting system of equations. The solutions give the points of tangency, and the lines through these points and (27, 3) are the desired tangent lines. The exact computations involve solving a quadratic equation and it'll give two slopes for the tangent line that passes through the point (27,3).
Learn more about Tangent Lines to Ellipse here:https://brainly.com/question/18917385
#SPJ3
An air-water vapor mixture gas enters an insulated mixing chamber at 300 K, 1 atm, 60 % relative humidity with a mass flow rate of 1 kg/s. A second steam of moist air enters at 380 K, 1 bar, 80% relative humidity at a mass flow rate of 0.5 kg/s. Assume the mixing takes place completely and any condensed liquid or vapor mixture exit at 1 bar. Determine: (a) The humidity ratio for both entering streams. (b) The humidity ratio and the temperature of the mixed stream exiting the control volume. (c) The amount of liquid condensate that leaves the control volume. (d) Challenge: Determine the rate of entropy production, in kW/K.
Answer:
i don't know sorry hope this helps
Step-by-step explanation:
The logistic growth function at right describes the number of people, f(t), who have become ill with influenza t weeks after its initial outbreak in a particular community. f (t )equals StartFraction 107 comma 000 Over 1 plus 4200 e Superscript negative t EndFraction.
a. How many people became ill with the flu when the epidemic began?
b. How many people were ill by the end of the fourth week?
c. What is the limiting size of the population that becomes ill?
Answer:
Part (a): 25 people became ill with the flu when the epidemic began.
Part (b): 1373 people were ill by the end of the fourth week.
Part (c): The limiting size of the population that becomes ill is 107,000.
Step-by-step explanation:
Consider the provided logistic growth function
[tex]f (t )=\frac{ 107,000}{1 +4200e^{-t}}[/tex]
Part (a) How many people became ill with the flu when the epidemic began?
Substitute t = 0 in above function.
[tex]f (t )=\frac{ 107,000}{1 +4200e^{-0}}[/tex]
[tex]f (t )=\frac{ 107,000}{4201}[/tex]
[tex]f (t )=25.47[/tex]
Hence, 25 people became ill with the flu when the epidemic began.
Part (b) How many people were ill by the end of the fourth week?
Substitute t = 4 in above function.
[tex]f (t )=\frac{ 107,000}{1 +4200e^{-4}}[/tex]
[tex]f (t )=1373.10[/tex]
Hence, 1373 people were ill by the end of the fourth week.
Part (c) What is the limiting size of the population that becomes ill?
Substitute t = ∞ in above function.
[tex]f (t )=\frac{ 107,000}{1 +4200e^{-\infty}}[/tex]
[tex]f (t )=\frac{ 107,000}{1 +0}[/tex]
[tex]f (t )=107,000[/tex]
Hence, the limiting size of the population that becomes ill is 107,000.
Using the logistic growth function, the number of sick people at the start of the epidemic and at the end of the fourth week can be found by substituting the appropriate values for time into the function. The limiting size of the potentially ill population is the maximum value of the function, which is 107,000.
Explanation:The logistic growth function provided describes the number of people, represented by f(t), who have become ill with influenza, t weeks after its initial outbreak. The function is given as f(t) = 107000/(1 + 4200 * e-t).
a. At the beginning of the epidemic (i.e., when t=0), the number of ill people, f(0), can be calculated by substituting 0 for t in the equation, resulting in 107,000/(1+4200) people.
b. By the end of the fourth week (i.e., when t=4), the number of ill people, f(4), can be calculated by substituting 4 for t in the equation.
c. The limiting size of the population that becomes ill is represented by the maximum value the growth function can take, which in this case is 107,000 (as seen by the numerator of the function). This means that illness will eventually spread to reach a potential maximum of 107,000 people in this specific community.
Learn more about Logistic Growth Function here:https://brainly.com/question/30763887
#SPJ11
A financial analyst wanted to estimate the mean annual return on mutual funds. A random sample of funds' returns shows an average rate of 12%. If the population standard deviation is assumed to be 4%, the 95% confidence interval estimate for the annual return on all mutual funds is
A. 0.037773 to 0.202227
B. 3.7773% to 20.2227%
C. 59.98786% to 61.01214%
D. 51.7773% to 68.2227%
E. 10.988% to 13.012%
A financial analyst wanted to estimate the mean annual return on mutual funds. A random sample of 60 funds' returns shows an average rate of 12%. If the population standard deviation is assumed to be 4%, the 95% confidence interval estimate for the annual return on all mutual funds is
A. 0.037773 to 0.202227
B. 3.7773% to 20.2227%
C. 59.98786% to 61.01214%
D. 51.7773% to 68.2227%
E. 10.988% to 13.012%
Answer: E. 10.988% to 13.012%
Step-by-step explanation:
Given;
Mean x= 12%
Standard deviation r = 4%
Number of samples tested n = 60
Confidence interval is 95%
Z' = t(0.025)= 1.96
Confidence interval = x +/- Z'(r/√n)
= 12% +/- 1.96(4%/√60)
= 12% +/- 0.01214%
Confidence interval= (10.988% to 13.012%)
The radius of a sphere increases at a constant rate of 2 com/min at the time when the volume of the sphere is 40 cm^3ç What is the rate of increase of the volume in cm^3/min?
Answer:
[tex]\frac{dV}{dt}=525 cm^{3}/min[/tex]
Step-by-step explanation:
The volume of a sphere is:
[tex]V=\frac{4}{3}\pi r^{3}[/tex] (1)
We know that:
dr/dt = 2 cm/min (increasing rate of radius)V = 40 cm³If we take the derivative of (1) with respect of time t, we ca n find the rate of increase of the volume.
[tex]\frac{dV}{dt}=\frac{4}{3}\pi 3r^{2}\frac{dr}{dt}=4\pi r^{2}\frac{dr}{dt}[/tex] (2)
We also know that the volume is 40 cm³, then using the (1) we can get the radius at this value.
Solving (1) for r, we have:
[tex]r=\left(\frac{3\cdot V}{4\pi}\right)^{1/3}=\left(\frac{3\cdot 400}{4\pi}\right)^{1/3}=4.57 cm[/tex]
Finally dV/dt will be:
[tex]\frac{dV}{dt}=4\pi (4.57)^{2}\cdot 2=525 cm^{3}/min[/tex]
I hope it helps you!
Periodically, Merrill Lynch customers are asked to evaluate Merrill Lynch financial consultants and services. Higher ratings on the client satisfaction survey indicate better service, with 7 the maximum service rating. Independent samples of service ratings for two financial consultants are summarized here. Consultant A has 10 years of experience, whereas consultant B has 1 year of experience. Use α= .05 and test to see whether the consultant with more experience has the higher population mean service rating.
Consultant A: n = 16, x = 6.82, s = 0.64
Consultant B: n = 10, x = 6.25, s = 0.75
a. State the null and alternative hypotheses.
b. Compute the value of the test statistic.
c. What is the p-value?
d. What is your conclusion?
Answer:
See the explanation
Step-by-step explanation:
(a)
H0: Consultant with more experience has the higher population mean service rating.
H1: Consultant with more experience doesn't have the higher population mean service rating.
(b)
t = 1.9923 (see the attached image)
(c)
The degrees of freedom for the test statistic,
df = 16
The P-value of the one tailed t- test with 16 degrees of freedom is,
P−value = tdist(X,df,tails)
P-value = tdist(1.9923,16,1)
P-value = 0.032
(d)
Since, P-value 0.032 is less than the significance level 0.05, there is an enough evidence to reject the null hypothesis.
Hence, there is a sufficient evidence to conclude that Consultant with more experience doesn't have the higher population mean service rating.
Hope this helps!
Five individuals from an animal population thought to be near extinction in a certain region have been caught, tagged, and released to mix into the population. After they have had an opportunity to mix, a random sample of 10 of these animals is selected. Let X = the number of tagged animals in the second sample. Assuming there is a total of 25 animals of this type in the region, what are E(X) and Var(X)?
Answer:
[tex]E(X)= n\frac{M}{N}=10 \frac{5}{25}=2[/tex]
[tex]Var(X)=n \frac{M}{N}\frac{N-M}{N}\frac{N-n}{N-1}=10\frac{5}{25}\frac{25-5}{25}\frac{25-10}{25-1}=1[/tex]
Step-by-step explanation:
Previous concepts
The hypergeometric distribution is a discrete probability distribution that its useful when we have more than two distinguishable groups in a sample and the probability mass function is given by:
[tex]P(X=k)= \frac{(MCk)(N-M C n-k)}{NCn}[/tex]
Where N is the population size, M is the number of success states in the population, n is the number of draws, k is the number of observed successes
The expected value and variance for this distribution are given by:
[tex]E(X)= n\frac{M}{N}[/tex]
[tex]Var(X)=n \frac{M}{N}\frac{N-M}{N}\frac{N-n}{N-1}[/tex]
What is the distribution of X?
For this case the random variable X follows a hypergometric distribution.
Compute the values for E(X) and Var(X)
For this case n=10, M=5, N=25, so then we can replace into the formulas like this:
[tex]E(X)= n\frac{M}{N}=10 \frac{5}{25}=2[/tex]
[tex]Var(X)=n \frac{M}{N}\frac{N-M}{N}\frac{N-n}{N-1}=10\frac{5}{25}\frac{25-5}{25}\frac{25-10}{25-1}=1[/tex]
What is the probability that none of the animals in the second sample are tagged?
So for this case we want this probability:
[tex]P(X=0)= \frac{(5C0)(25-5 C 10-0)}{25C10}=\frac{1*184756}{3268760}=0.0565[/tex]
What is the probability that all of the animals in the second sample are tagged?
So for this case we want this probability:
[tex]P(X=5)= \frac{(5C5)(25-5 C 10-5)}{25C10}=\frac{1*15504}{3268760}=0.00474[/tex]
equation form for
slope =3
point (2, 17)
Answer:
The equation of the line with slope is 3 and point (2,17) is [tex]y=3x+11[/tex]
Step-by-step explanation:
Given slope is 3 ie., m=3 and point (2,17)
To find the equation of the line with slope and a point:
Using slope point formula
[tex]y-y_{1}=m(x-x_{1})[/tex]
Let the point (2,17) be [tex](x_{1},y_{1})[/tex]
Substitute the values of m=3 and point (2,17)
[tex]y-y_{1}=m(x-x_{1})[/tex]
[tex]y-17=3(x-2)[/tex]
[tex]y-17=3x-6[/tex]
[tex]y=3x-6+17[/tex]
[tex]y=3x+11[/tex]
Therefore the equation of the line is [tex]y=3x+11[/tex]
Extreme cold and hot temperatures are known to affect the operation of electronic components. Winter is approaching and you are interested in the mean minimum temperature that will damage an iPod. As a research project, 9 iPods were tested to see what minimum temperature damaged the electronic component. The damaging temperature averaged 5 ºF with a standard deviation of 3 ºF. Find a 95% confidence interval for the true mean minimum temperature that will damage an iPod. (Disclaimer: Apple recommends that to "keep iPod comfy," the iPod’s battery should be kept between temperatures of 32 ºF and 95 ºF.)If the question requires a test of significance, your solution should clearly show the four steps to the test. In addition, you should show that you have checked that the conditions for inference are met.Step 1: State the null and alternative hypothesis.Step 2: Calculate the test statistic.Step 3: Find the p-value.Step 4: State your conclusion in the context of the problem. (Do not just say "Reject H0" or "Do not reject H0.")If the question requires a confidence interval, be sure to make a statement about the confidence interval in context of the problem.
Answer:
A 95% confidence interval for the true mean minimum temperature that will damage an iPod is between 2.55°F and 7.45°F
Test statistic(Z) = 2.31
P-value = 0.0104
Step-by-step explanation:
Step 1
Null hypothesis: The average damaging temperature of nine iPods is 5°F
Alternate hypothesis: The average damaging temperature of nine iPods differs from 5°F
Step 2
Mean=5°F, Sd=3, df=n-1=9-1=8
The t-value corresponding to 8 degrees of freedom and 95% confidence level (5% significance level) is 2.306
Confidence Interval(CI) = (mean + or - t×sd/√n)
CI = (5 + 2.306×3/√8) = 5 + 6.918/2.828= 5+2.45=7.45°F
CI = (5 - 2.306×3/√8) = 5-2.45 = 2.55°F
Z = (sample mean - population mean)/(sd÷√n) = (5-2.55)/(3÷√8) = 2.45/1.061 = 2.31
Step 3
Using the standard distribution table, the cumulative area to the left of Z = 2.31 is 0.9896
P-value = 1 - 0.9896 = 0.0104
Step 4
Conclusion: A 95% confidence interval for the true mean minimum temperature that will damage an iPod is between 2.55°F and 7.45°F