Answer:
Step-by-step explanation:
For the disease having force of mortality µ.
we apply exponential distribution law
probability of dying within 20 years
p( x <20) = [tex]1-e^{-\mu}[/tex] = .1
[tex]e^{-\mu}[/tex] = .9
For the disease having force of mortality 2µ.
we apply exponential distribution law
probability of dying within 20 years
p( x <20) = 1 - [tex]e^{-2\mu}[/tex]
= 1 - ( .9)²
= 1 - .81
= .19
or 19%
The histogram displays the number of 2012 births among U.S. women ages 10 to 50 . Each bin represents an interval of two years, and the height of each bin represents the frequency with which the data fall within that interval?
Answer:
Number of births to women below 22 years of age: 830
% of births occurred to women of age between 34 and 36: 6.35%
Step-by-step explanation:
There are two parts to this question:
To calculate the number of births, we look at the histogram below.
We see that each bar has a number on top, suggesting that particular for the age limit. Number of births to women below age of 22, we start adding all numbers below the mark of 22 on x-axis:
⇒ 39+134+29+363 = 830
To calculate the percentage, we divide the number of births in that particular interval by total number of births and then multiply by 100.
To calculate the total number of births, we add all the numbers on the top of the bars:
⇒ 39+ 134+294+363+391+425+460+474+432+343+250+163+98+49+17+4+1 Total births = 3937
[tex]\frac{250}{3937} \times 100\\ 0.0635 \times 100\\= 6.35 \%[/tex]
A sample of 16 people is taken and their weights are measured. The standard deviation of these 16 measurements is computed to be 5.8. What is the variance of these measurements?
Answer:
The variance of given sample is 33.64 square pounds.
Step-by-step explanation:
We are given the following in the question:
Sample size, n = 16
Standard deviation, s = 5.8 pounds
We have to find the variance of the given sample.
Variance is the square of the standard deviation.
[tex]\text{Variance} = (\text{Standard Deviation})^2\\= (5.8\text{ pounds})^2\\=33.64\text{ pound}^2[/tex]
Thus, the variance of given sample is 33.64 square pounds.
A square matrix A is said to be idempotent iff A2 = A. (i) Show that if A is idempotent, then so is I − A. (ii) Show that if A is idempotent, then the matrix 2A − I is also invertible. Hint: Same as before, guess the inverse and check your answer with the definition of inverse.
Answer:
Step-by-step explanation:
Given that A is a square matrix and A is idempotent
[tex]A^2 = A[/tex]
Consider I-A
i) [tex](I-A)^2 = (I-A).(I-A)\\= I^2 -2A.I+A^2\\= I-2A+A\\=I-A[/tex]
It follows that I-A is also idempotent
ii) Consider the matrix 2A-I
[tex](2A-I).(2A-I)=\\4A^2-4AI+I^2\\= 4A-4A+I\\=I[/tex]
So it follows that 2A-I matrix is its own inverse.
Explain the meaning of each of the following. (a) lim x → −3 f(x) = [infinity] The values of f(x) can be made arbitrarily close to 0 by taking x sufficiently close to (but not equal to) −3. The values of f(x) can be made arbitrarily large by taking x sufficiently close to (but not equal to) −3.
Answer:
The right answer is option 3.
lim x → −3 f(x) = [infinity] means the values of f(x) can be made arbitrarily large by taking x sufficiently close to (but not equal to) −3.
Step-by-step explanation:
The limit of a function is a fundamental concept concerning the behavior of that function near a particular input.
A function f assigns an output f(x) to every input x. We say the function has a limit L at an input a: this means f(x) gets closer and closer to L as x moves closer and closer to a. More specifically, when f is applied to any input sufficiently close to a, the output value is forced arbitrarily close to L.
That is,
lim x → a f(x) = L
Hope this helps!
The limit lim x → −3 f(x) = [infinity] means that as x values get closer to -3 (without becoming -3), the value of the function f(x) goes towards infinity i.e., it grows without bound. This is akin to certain function behaviors near a value at which an asymptote is present. However, the second part about f(x) values getting close to 0 seems contradiction to the first statement.
Explanation:The statement lim x → −3 f(x) = [infinity] is related to a concept in Calculus known as a limit. When we say that the limit of f(x) as x approaches -3 is infinity, we mean that as we make x values closer and closer to -3 (without letting x actually be -3), the value of the function f(x) becomes larger and larger without bound, i.e., approaches infinity.
This is similar to some function behaviors near an asymptote. For example, the function y = 1/x has a vertical asymptote at x = 0, where y approaches infinity as x approaches zero from either direction. Here, as x gets arbitrarily close to 0, the value of y = 1/x gets arbitrarily large, or 'approaches infinity'.
On the other hand, when the question states, 'The values of f(x) can be made arbitrarily close to 0 by taking x sufficiently close to (but not equal to) -3', it signifies the tendency of the function values to get closer and closer to 0 as x gets closer to -3. This indicates a certain limit behavior, but it seems to be contradictory with the first part where the limit was stated to be infinity. It is important to scrutinize the function's properties and behavior around x = -3 carefully.
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Consider the following vector-valued function:~h(t) =〈2 sin(3t),3 cos(3t),√5 sin(3t)〉0≤t≤2π3This defines a smooth parameterized curve.(a) Find the unit tangent vector~T(t) for 0≤t≤2π3.(b) Find all of the values oftin the interval 0≤t≤2π3where~h(t) and~T(t) areorthogonal.(c) Show that the curve~h(t) lies on a sphere. What is the radius of the sphere?
Answer:
a) h'(t)= (6cos3t,-9sin3t,3[tex]\sqrt[]{5}[/tex]cos3t)
b) t=0.93994736+πn/3
c) Magnitude of h(t) is 3 which is a constant, so h(t) lies on a sphere
Step-by-step explanation:
An algorithm takes 0.5 seconds to run on an input of size 100. How long will it take to run on an input of size 1000 if the algorithm has a running time that is linear? quadratic? log-linear? cubic?
Answer:
linear: 5s
quadratic: 50s
log-linear: 0.75 s
cubic: 500s
Step-by-step explanation:
Let [tex]t_1,t_2[/tex] be the running time associated with the input of sizes [tex] s_1,s_2[/tex]
If the running time is linear
[tex]t_2 = t_1\frac{s_2}{s_1} = 0.5*\frac{1000}{100} = 0.5*10 = 5s[/tex]
If the running time is quadratic
[tex]t_2 = t_1\left(\frac{s_2}{s_1}\right)^2 = 0.5*\left(\frac{1000}{100}\right)^2 = 0.5*10^2 = 50s[/tex]
If the running time is log-linear
[tex]t_2 = t_1\frac{log(s_2)}{log(s_1)} = 0.5*\frac{log(1000)}{log(100)} = 0.5*1.5 = 0.75s[/tex]
If the running time is cubic:
[tex]t_2 = t_1\left(\frac{s_2}{s_1}\right)^3 = 0.5*\left(\frac{1000}{100}\right)^3 = 0.5*10^3 = 500s[/tex]
A new drug to treat psoriasis has been developed and is in clinical testing. Assume that those individuals given the drug are examined before receiving the treatment and then again after receiving the treatment to determine if there was a change in their symptom status. If the initial results showed that 2.0% of individuals entered the study in remission, 77.0% of individuals entered the study with mild symptoms, 16.0% of individuals entered the study with moderate symptoms, and 5.0% entered the study with severe symptoms calculate and interpret a chi-squared test to determine if the drug was effective treating psoriasis given the information below from the final examination.
Answer:
Step-by-step explanation:
Solution:-
State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.
Null hypothesis: The distribution of severity of psoriasis cases at the end and prior are same.
Alternative hypothesis: The distribution of severity of psoriasis cases at the end and prior are different.
Formulate an analysis plan. For this analysis, the significance level is 0.05. Using sample data, we will conduct a chi-square goodness of fit test of the null hypothesis.
Analyze sample data. Applying the chi-square goodness of fit test to sample data, we compute the degrees of freedom, the expected frequency counts, and the chi-square test statistic. Based on the chi-square statistic and the degrees of freedom, we determine the P-value.
DF = k - 1 = 4 - 1
D.F = 3
(Ei) = n * pi
Category observed Num expected num [(Or,c -Er,c)²/Er,c]
Remission 380 20 6480
Mild
symptoms 520 770 81.16883117
Moderate
symptoms 95 160 24.40625
Severe
symptom 5 50 40.5
Sum 1000 1000 6628.075081
Χ2 = Σ [ (Oi - Ei)2 / Ei ]
Χ2 = 6628.08
Χ2Critical = 7.81
where DF is the degrees of freedom, k is the number of levels of the categorical variable, n is the number of observations in the sample, Ei is the expected frequency count for level i, Oi is the observed frequency count for level i, and Χ2 is the chi-square test statistic.
The P-value is the probability that a chi-square statistic having 3 degrees of freedom is more extreme than 6628.08.
We use the Chi-Square Distribution Calculator to find P(Χ2 > 19.58) =less than 0.000001
Interpret results. Since the P-value (almost 0) is less than the significance level (0.05), we cannot accept the null hypothesis.
We reject H0, because 6628.08 is greater than 7.81. We have statistically significant evidence at alpha equals to 0.05 level to show that distribution of severity of psoriasis cases at the end of the clinical trial for the sample is different from the distribution of the severity of psoriasis cases prior to the administration of the drug suggesting the drug is effective.
The chi-square test is a statistical method that determines if there's a significant difference between observed and expected frequencies in different categories, such as symptom status in this clinical trial. Without post-treatment numbers, we can't run the exact test. However, if the test statistic exceeded the critical value, we could conclude that the drug significantly affected symptom statuses.
Explanation:This question pertains to the use of a chi-squared test, which is a statistical method used to determine if there's a significant difference between observed frequencies and expected frequencies in one or more categories. For this case, the categories are the symptom statuses (remission, mild, moderate, and severe).
To conduct a chi-square test, you first need to know the observed frequencies (the initial percentages given in the question) and the expected frequencies (the percentages after treatment). As the question doesn't provide the numbers after treatment, I can't perform the exact chi-square test.
If the post-treatment numbers were provided, you would compare them to the pre-treatment numbers using the chi-squared formula, which involves summing the squared difference between observed and expected frequencies, divided by expected frequency, for all categories. The result is a chi-square test statistic, which you would then compare to a critical value associated with a chosen significance level (commonly 0.05) to determine if the treatment has a statistically significant effect.
To interpret a chi-square test statistic, if the calculated test statistic is larger than the critical value, it suggests that the drug made a significant difference in the distribution of symptom statuses. If not, we can't conclude the drug was effective.
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Keeping water supplies clean requires regular measurement of levels of pollutants. The measurements are indirect—a typical analysis involves forming a dye by a chemical reaction with the dissolved pollutant, then passing light through the solution and measuring its "absorbence." To calibrate such measurements, the laboratory measures known standard solutions and uses regression to relate absorbence and pollutant concentration. This is usually done every day. Here is one series of data on the absorbence for different levels of nitrates. Nitrates are measured in milligrams per liter of water.
Nitrates 50 50 100 200 400 800 1200 1600 2000 2000
Absorbence 7.0 7.6 12.7 24.0 47.0 93.0 138.0 183.0 231.0 226.0
The calibration process sets nitrate level and measures absorbence. The linear relationship that results is used to estimate the nitrate level in water from a measurement of absorbence.
a. What is the equation of the line used to estimate nitrate level?
b. What does the slope of this line say about the relationship between nitrate level and absorbence?
c. What is the estimated nitrate level in a water specimen with absorbence 40?
Answer:
a) Equation is
[tex]y = 0.1135x+1.590[/tex]
b) Slope = 0.1135 represents the change in y for a unit change in x
i.e. When nitrate content is increasedby 1, absorbence is increased by 0.1135
Step-by-step explanation:
Nitrates Absorbence
x y
50 7
50 7.6
100 12.7
200 24
400 47
800 93
1200 138
1600 183
2000 231
2000 226
SUMMARY OUTPUT
Regression Statistics
Multiple R 0.999911043
R Square 0.999822094
Adjusted R Square 0.999799856
Standard Error 1.2890282
Observations 10
Coefficients
Intercept 1.589782721
x 0.113500259
we get regression line as
y = 0.1135x+1.590
a) Equation is
[tex]y = 0.1135x+1.590[/tex]
b) Slope = 0.1135 represents the change in y for a unit change in x
i.e. When nitrate content is increasedby 1, absorbence is increased by 0.1135
A small island is 3 miles from the nearest point P on the straight shoreline of a large lake. If a woman on the island can row a boat 3 miles per hour and can walk 4 miles per hour, where should the boat be landed in order to arrive at a town 12 miles down the shore from P in the least time? Let x be the distance between point P and where the boat lands on the lakeshore. Hint: time is distance divided by speed.
Answer:
The trip consists of two parts. The rowing part is the hypotenuse of right angled triangle
whose sides are the distance from P to the island, which is 5, and the distance between P and
the landing point of the rowboat on the shore, which is x
so this part of trip is sqrt(25+ x^2)
The 2nd part is the walking part, which is (8-x)
Distance = rate times time (D = rt), so to get the time you have t = D/r. We must divide each
of the trip by the appropriate rate to get the time.
a) T(x) = sqrt(25+x^2)/3 + (8-x)/4
To find minimum time required take derivative of the T(x) function and find it's zeros
T'(x) = x/(3(sqrt(25+x^2)) - 1/4 = 0
x/(3(sqrt(25+x^2)) = 1/4
4x = 3sqrt(25+x^2
16x^2 = 9(25+x^2) = 225 + 9x^2
7x^2 = 225
x^2 = 225/7
x = sqrt(225/7) = 5.669467 miles
T(x) = 3.602386382 hours
Step-by-step explanation:
The point where the boat should be landed can be found by expressing
the distance travelled on the boat and walking as a function of time.
The point where the boat should be landed is the point 3.4 miles from the
point P towards the town.
Reasons:
x represent the distance from point P to the boat landing point.
Therefore, distance of rowing the boat = √((12 - x)² + 3²)
The total time, t, is therefore;
[tex]t = \dfrac{12-x}{4} +\dfrac{\sqrt{x^2 + 3^2} }{3}[/tex]
When the time is minimum, we get;
[tex]\dfrac{dt}{dx} = \dfrac{d}{dx} \left( \dfrac{12-x}{4} +\dfrac{\sqrt{x^2 + 3^2} }{3} \right) = \dfrac{12\cdot \left(-3 + 4 \cdot\dfrac{2 \cdot x }{2\cdot \sqrt{x^2 + 9} } \right)}{144}[/tex]
[tex]\dfrac{12\cdot \left(-3 + 4 \cdot\dfrac{2 \cdot x }{2\cdot \sqrt{x^2 + 9} } \right)}{144} = -\dfrac{1}{4} +\dfrac{x }{3 \cdot \sqrt{x^2 +9} }[/tex]
[tex]\dfrac{x }{3 \cdot \sqrt{x^2 +9} } = \dfrac{1}{4}[/tex]
4·x = 3·√(x² + 9)
16·x² = 9·(x² + 9)
7·x² = 81
[tex]x = \dfrac{9 \cdot \sqrt{7} }{7}[/tex]
x ≈ 3.4 miles.
The point where the boat should be landed is the point approximately 3.4
miles from the point P in the direction of the town.
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Harry notes that the state sales tax went from 2% to 2.5%, which he says is not too bad because it's just a one-half percent increase. But Linda says that it really is bad because it's a 25% increase. Who's right, and why?
We are required to calculate the percentage increase in tax and determine who is right.
The percentage increase in tax is 25% and Linda is very correct
percentage increase = difference in tax /
percentage increase = difference in tax / old tax × 100
old tax = 2%
New tax = 2.5%
Difference = New tax - old tax
= 2.5% - 2%
= 0.5%
percentage increase = difference in tax /
percentage increase = difference in tax / old tax × 100
= 0.5% / 2% × 100
= 0.25 × 100
= 25%
Therefore, the percentage increase in tax is 25% and Linda is very correct
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The admission price was $1.00 in 1909. How much would the Speedway have had to charge in 1999 to match the purchasing power of $1 in 1909? In other words, how much was that in 1999? (Don't use a $ sign, use 2 decimal places.)
Answer: 13.04
Here are some consumer price indexes from the past 100+ years:
Year CPI
1909 9.1
1919 17.3
1929 17.1
1939 13.9
1949 23.8
1959 29.1
1969 36.7
1979 72.6
1989 118.3
1999 166.6
2009 214.5
2015 238.5
The admission price was $1.00 in 1909. How much would the Speedway have had to charge in 1989 to match the purchasing power of $1 in 1909? In other words, how much was that in 1989?
If s is an increasing function, and t is a decreasing function, find Cs(X),t(Y ) in terms of CX,Y .
Answer:
C(X,Y)(a,b)=1−C(s(X),t(Y))(a,1−b).
Step-by-step explanation:
Let's introduce the cumulative distribution of (X,Y), X and Y :
F(X,Y)(x,y)=P(X≤x,Y≤y)
FX(x)=P(X≤x) FY(y)=P(Y≤y).Likewise for (s(X),t(Y)), s(X) and t(Y) :
F(s(X),t(Y))(u,v)=P(s(X)≤u
t(Y)≤v)Fs(X)(u)=P(s(X)≤u) Ft(Y)(v)=P(t(Y)≤v).Now, First establish the relationship between F(X,Y) and F(s(X),t(Y)) :
F(X,Y)(x,y)=P(X≤x,Y≤y)=P(s(X)≤s(x),t(Y)≥t(y))
The last step is obtained by applying the functions s and t since s preserves order and t reverses it.
This can be further transformed into
F(X,Y)(x,y)=1−P(s(X)≤s(x),t(Y)≤t(y))=1−F(s(X),t(Y))(s(x),t(y))
Since our random variables are continuous, we assume that the difference between t(Y)≤t(y) and t(Y)<t(y)) is just a set of zero measure.
Now, to transform this into a statement about copulas, note that
C(X,Y)(a,b)=F(X,Y)(F−1X(a), F−1Y(b))
Thus, plugging x=F−1X(a) and y=F−1Y(b) into our previous formula,
we get
F(X,Y)(F−1X(a),F−1Y(b))=1−F(s(X),t(Y))(s(F−1X(a)),t(F−1Y(b)))
The left hand side is the copula C(X,Y), the right hand side still needs some work.
Note that
Fs(X)(s(F−1X(a)))=P(s(X)≤s(F−1X(a)))=P(X≤F−1X(a))=FX(F−1X(a))=a
and likewise
Ft(Y)(s(F−1Y(b)))=P(t(Y)≤t(F−1Y(b)))=P(Y≥F−1Y(b))=1−FY(F−1Y(b))=1−b
Combining all results we obtain for the relationship between the copulas
C(X,Y)(a,b)=1−C(s(X),t(Y))(a,1−b).
In a shipment of 58 vials, only 16 do not have hairline cracks. If you randomly select 2 vials from the shipment, what is the probability that none of the 2 vials have hairline cracks?
Answer:
0.0726 or 7.26%
Step-by-step explanation:
When choosing the first vial, there is a 16 in 58 chance that the vial does not have a hairline crack. When choosing the second vial, since on good vial was already picked, there is a 15 in 57 chance that the vial does not have a hairline crack. The probability that none of the 2 vials have hairline cracks is:
[tex]P = \frac{16}{58}*\frac{15}{57}\\P=0.0726[/tex]
There is a 0.0726 or 7.26% chance that none of the 2 vials have a hairline crack.
Solve the system using the substitution or elimination method. How many solutions are there to this system?
Answer:
[tex] -3*(3y+2) + 9y = -6[/tex]
[tex] -9y -6 + 9y = -6[/tex]
[tex]-6=-6[/tex]
So then as we can see we can have infinite solutions.
[tex]S= [(x, \frac{x-2}{3}) , x \in R][/tex]
Step-by-step explanation:
Assuming the following system of equations:
[tex] 2x-6y =4[/tex] (1)
[tex] -3x+9y =-6[/tex] (2)
For this case we can use the substitution method in order to find the possible solutions for the system.
If we solve for x from equation (1) we got:
[tex] 2x = 6y +4[/tex]
[tex] x = 3y +2 [/tex] (3)
Now we can replace equation (3) into equation (2) and we got:
[tex] -3*(3y+2) + 9y = -6[/tex]
[tex] -9y -6 + 9y = -6[/tex]
[tex]-6=-6[/tex]
So then as we can see we can have infinite solutions.
And the possible solutions are for a fixed value of x, we can solve y from equation (3) and we got:
[tex] y = \frac{x-2}{3}[/tex]
So the solution would be: [tex]S= [(x, \frac{x-2}{3}) , x \in R][/tex]
For these types of questions, first click the line tool on the tool palette labelled PFloor, and plot by clicking your mouse for the first end-point -- touching the vertical axis then moving your mouse to the right and clicking again for the second end-point. The new line should intersect both the D1 and S1 lines and have a height greater than 50 as measured on the vertical axis.
To Plotting lines , use the PFloor line tool and click your mouse for the first and second end-points, ensuring that the line intersects both the D1 and S1 lines and has a height greater than 50.
To plot the line described in the question, follow these steps:
Select the line tool on the tool palette labeled PFloor.
Click your mouse for the first end-point on the vertical axis.
Move your mouse to the right and click again for the second end-point.
The new line should intersect both the D1 and S1 lines and have a height greater than 50 on the vertical axis.
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An elementary school is offering 2 language classes: one in Spanish (S) and one in French (F). Given that P(S) = 50%, P(F) = 40%, P(S ∪ F) = 70%, find the probability that a randomly selected student (a) is taking Spanish given that he or she is taking French; (b) is not taking French given that he or she is not taking Spanish. 2. A pair of fair dice is rolled until a sum of either 5 or 7 appears.
Answer:
(a) Probability that a randomly selected student is taking Spanish given that he or she is taking French = 0.5 .
(b) Probability that a randomly selected student is not taking French given that he or she is not taking Spanish = 0.6 .
Step-by-step explanation:
We are given that an elementary school is offering 2 language classes ;
Spanish Language is denoted by S and French language is denoted by F.
Also we are given, P(S) = 0.5 {Probability of students taking Spanish language}
P(F) = 0.4 {Probability of students taking French language}
[tex]P(S\bigcup F)[/tex] = 0.7 {Probability of students taking Spanish or French Language}
We know that, [tex]P(A\bigcup B)[/tex] = [tex]P(A) + P(B) -[/tex] [tex]P(A\bigcap B)[/tex]
So, [tex]P(S\bigcap F)[/tex] = [tex]P(S) + P(F) - P(S\bigcup F)[/tex] = 0.5 + 0.4 - 0.7 = 0.2
[tex]P(S\bigcap F)[/tex] means Probability of students taking both Spanish and French Language.
Also, P(S)' = 1 - P(S) = 1 - 0.5 = 0.5
P(F)' = 1 - P(F) = 1 - 0.4 = 0.6
[tex]P(S'\bigcap F')[/tex] = 1 - [tex]P(S\bigcup F)[/tex] = 1 - 0.7 = 0.3
(a) Probability that a randomly selected student is taking Spanish given that he or she is taking French is given by P(S/F);
P(S/F) = [tex]\frac{P(S\bigcap F)}{P(F)}[/tex] = [tex]\frac{0.2}{0.4}[/tex] = 0.5
(b) Probability that a randomly selected student is not taking French given that he or she is not taking Spanish is given by P(F'/S');
P(F'/S') = [tex]\frac{P(S'\bigcap F')}{P(S')}[/tex] = [tex]\frac{1- P(S\bigcup F)}{1-P(S)}[/tex] = [tex]\frac{0.3}{0.5}[/tex] = 0.6 .
Note: 2. A pair of fair dice is rolled until a sum of either 5 or 7 appears ; This question is incomplete please provide with complete detail.
A financial talk show host claims to have a 55.3 % success rate in his investment recommendations. You collect some data over the next few weeks, and find that out 10 recommendations, he was correct 3 times. If the claim is correct and the performance of recommendations is independent, what is the probability that you would have observed 4 or fewer successfu
Answer:
There is a 25.52% probability of observating 4 our fewer succesful recommendations.
Step-by-step explanation:
For each recommendation, there are only two possible outcomes. Either it was a success, or it was a failure. So we use the binomial probability distribution to solve this problem.
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.
In this problem we have that:
[tex]p = 0.553, n = 10[/tex]
If the claim is correct and the performance of recommendations is independent, what is the probability that you would have observed 4 or fewer successful:
This is
[tex]P(X \leq 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4)[/tex]
In which
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{10,0}.(0.553)^{0}.(0.447)^{10} = 0.0003[/tex]
[tex]P(X = 1) = C_{10,1}.(0.553)^{1}.(0.447)^{9} = 0.0039[/tex]
[tex]P(X = 2) = C_{10,2}.(0.553)^{2}.(0.447)^{8} = 0.0219[/tex]
[tex]P(X = 3) = C_{10,3}.(0.553)^{3}.(0.447)^{7} = 0.0724[/tex]
[tex]P(X = 4) = C_{10,4}.(0.553)^{4}.(0.447)^{6} = 0.1567[/tex]
[tex]P(X \leq 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) = 0.0003 + 0.0039 + 0.0219 + 0.0724 + 0.1567 = 0.2552[/tex]
There is a 25.52% probability of observating 4 our fewer succesful recommendations.
The deck for a card game is made up of 108 cards. Twenty-five each are red, yellow, blue, and green, and eight are wild cards. Each player is randomly dealt a seven-card hand.
(a) What is the probability that a hand will contain exactly two wild cards?
(b) What is the probability that a hand will contain two wild cards, two red cards, and three blue cards?
(a) The probability that a hand will contain exactly two wild cards is 0.076.
(b) The probability that a hand will contain two wild cards, two red cards, and three blue cards is 0.0007.
Let's solve these problems using the concept of combinations in probability.
Remember, [tex]C(n, k)[/tex] denotes the number of ways to choose k items from a set of n items, and is calculated as
[tex]C(n,k)=\frac{n!}{k!(n-k)!}[/tex]
where "!" denotes factorial. For example, [tex]5! = 5 \times 4 \times 3 \times 2 \times 1[/tex]
(a) The probability that a hand will contain exactly two wild cards:
The total number of ways to choose 7 cards out of 108 is [tex]C(108, 7)[/tex].
The number of ways to choose 2 wild cards out of 8 is [tex]C(8, 2)[/tex].
The number of ways to choose the remaining 5 cards out of the 100 non-wild cards is [tex]C(100, 5)[/tex].
So, the probability is [tex]\frac{C(8, 2) \times C(100, 5)}{C(108, 7)} \approx 0.076[/tex]
(b) The probability that a hand will contain two wild cards, two red cards, and three blue cards:
The number of ways to choose 2 wild cards out of 8 is [tex]C(8, 2)[/tex].
The number of ways to choose 2 red cards out of 25 is [tex]C(25, 2)[/tex].
The number of ways to choose 3 blue cards out of 25 is [tex]C(25, 3)[/tex].
So, the probability is [tex]\frac{C(8, 2) \times C(25, 2) \times C(25, 3)}{C(108, 7)} \approx 0.0007[/tex]
********Please show work*********
Kenen loves trains, especially those that run on narrow-gauge tracks. (The gauge
of a track measures how far apart the rails are.) He has decided to build a model
train of the Rio Grande, a popular narrow-gauge train.
Use the following information to help him know how big his model should be:
* The real track has a gauge of 3 feet (36 inches).
* His model railroad track has a gauge of 3/4 inches.
*The Rio Grande train he wants to model has driving wheels that measure 44 inches high.
Your Task: With your team, discuss what you know about the model train Kenen will build.
1) What scale factor should he use?
2) What will be the height of the driving wheels of his model?
Since the real track has a gauge of 3 feet but the model railroad track has a gauge of 3/4 inches, the scale factor must be 1/4, because you must follow the rule
"true measurement * scale factor = model measurement"
In fact, we have
[tex]3\cdot\dfrac{1}{4}=\dfrac{3}{4}[/tex]
This implies that the original driving wheels height, 44 inches, must be scaled down to
[tex]44\cdot\dfrac{1}{4}=11[/tex]
inches.
According to the 2010 Census, 11.4% of all housing units in the United States were vacant. A county supervisor wonders if her county is different from this proportion. She randomly selects 850 housing units in her county and finds that 129 of the housing units are vacant. Write the null hypothesis and the alternative hypothesis Do a Test of Hypothesis and write the P-value. Write your conclusion: Construct a 95% cl for the true proportion of vacant houses in the supervisor's county. Does the confidence interval support your conclusion. Explain briefly.
Answer:
Null hypothesis:[tex]p=0.114[/tex]
Alternative hypothesis:[tex]p \neq 0.114[/tex]
[tex]z=\frac{0.152 -0.114}{\sqrt{\frac{0.114(1-0.114)}{850}}}=3.49[/tex]
Since is a bilateral test the p value would be:
[tex]p_v =2*P(z>3.49)=0.00049[/tex]
So the p value obtained was a very 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.
[tex]0.152 - 1.96 \sqrt{\frac{0.152(1-0.152)}{850}}=0.128[/tex]
[tex]0.152 - 1.96 \sqrt{\frac{0.152(1-0.152)}{850}}=0.176[/tex]
And the 95% confidence interval would be given (0.128;0.176).
And support the conclusion obtained on the hypothesis test since the value of 0.114 is not in the confidence interval, so we have enough evidence to reject the null hypothesis.
Step-by-step explanation:
Data given and notation
n=850 represent the random sample taken
X=129 represent the number of housing units that are vacant.
[tex]\hat p=\frac{129}{850}=0.152[/tex] estimated proportion of housing units that are vacant.
[tex]p_o=0.114[/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 proportion is equal is 0.114 or not:
Null hypothesis:[tex]p=0.114[/tex]
Alternative hypothesis:[tex]p \neq 0.114[/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{0.152 -0.114}{\sqrt{\frac{0.114(1-0.114)}{850}}}=3.49[/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 assumed is [tex]\alpha=0.05[/tex]. The next step would be calculate the p value for this test.
Since is a bilateral test the p value would be:
[tex]p_v =2*P(z>3.49)=0.00049[/tex]
So the p value obtained was a very 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.
Confidence interval
The confidence interval would be given by this formula
[tex]\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]
For the 95% confidence interval the value of [tex]\alpha=1-0.95=0.05[/tex] and [tex]\alpha/2=0.025[/tex], with that value we can find the quantile required for the interval in the normal standard distribution.
[tex]z_{\alpha/2}=1.96[/tex]
And replacing into the confidence interval formula we got:
[tex]0.152 - 1.96 \sqrt{\frac{0.152(1-0.152)}{850}}=0.128[/tex]
[tex]0.152 - 1.96 \sqrt{\frac{0.152(1-0.152)}{850}}=0.176[/tex]
And the 95% confidence interval would be given (0.128;0.176).
And support the conclusion obtained on the hypothesis test since the value of 0.114 is not in the confidence interval, so we have enough evidence to reject the null hypothesis.
We first set the null and alternative hypothesis and then conduct a z-test for proportions to calculate the z-score and subsequently the p-value. We use the p-value to decide whether to reject the null hypothesis. Finally, we construct a 95% confidence interval for the true proportion of vacant houses and check if this supports our test conclusion.
Explanation:Firstly, define the proportion of vacant housing units in the country as p0 and in the randomly selected county as p. The null hypothesis (H0) states that the county isn't different, so H0: p = p0 = 0.114. The alternative hypothesis (Ha) would be that the county is different, so Ha: p ≠ 0.114.
Let's conduct a Test of Hypothesis using a z-test for proportions. The z-score is calculated as (p - p0) / sqrt((p0 * (1 - p0)) / n), where n represents the sample size. Substituting in your values, the z score will be calculated. This z-score can be used to find the p-value from a standard normal (Z) distribution table.
If the p-value is less than 0.05 (which is α, significance level), we reject the null hypothesis in favor of alternative hypothesis, else we do not reject the null hypothesis. Thus, our conclusion is formulated based on this p-value.
To construct a 95% confidence interval for the true proportion of vacant houses, we use the formula: p ± Z * sqrt((p * (1 - p)) / n). Here, Z will be the Z score corresponding to the desired confidence level, 95% (which is 1.96 for two-tailed test).
If the national proportion (0.114) doesn't lie within this interval, it supports our test conclusion of rejecting the null hypothesis and vice versa.
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Data for an economy show that the unemployment rate is 6 percent, the participation rate is 60 percent, and 200 million people 16 years or older are not in the labor force. How many people are in the labor force in this economy
Answer:
300 million people
Step-by-step explanation:
If the participation rate is 60% and 200 million people 16 years or older are not in the labor force, it means that 200 million corresponds to 40% of people 16 years or older. Since 60% of people 16 years or older are in the labor force, the total number of people in the labor force is given by:
[tex]n=\frac{200}{0.4}-200\\ n= 300\ million\ people[/tex]
300 million people are in the labor force in this economy.
Suppose you received a score of 95 out of 100 on exam 1 . The mean was 79 and the standard deviation was 8 . If your score on exam 2 is 90 out of 100 , and the mean was 60 with a standard deviation of 15 , then you did:
better on exam 1 .
worse on exam 1 .
the same on both exams.
worse on exam 2
Answer:
You did the same on both exams.
Step-by-step explanation:
To compare both the scores, we need to compute the z scores of both the exams and then compare the values. The formula for z-score is:
Z = (X - μ)/σ
Where X = score obtained
μ = mean score
σ = standard deviation
For Exam 1:
Z = (95 - 79)/8
= 16/8
Z = 2
For Exam 2:
Z = (90 - 60)/15
= 30/15
Z = 2
The z-scores for both the tests are same hence the third option is correct i.e. you did the same on both exams.
Your performance on exam 1 and exam 2 can be compared using Z-scores, which measure how many standard deviations a score is from the mean. You scored 2 standard deviations above the mean on both exams, so you did the same on both exams.
Explanation:In this question, your performance on exams is being compared relative to the mean of the class scores and their standard deviation. This is a concept in statistics known as Z-scores. The Z-score tells us how many standard deviations an observation (your score) is from the mean. The formula for Z-score is (observation - mean) / standard deviation.
For exam 1 your Z - score is (95-79) / 8 which equals 2. This means you scored 2 standard deviations above the mean on exam 1. For exam 2, your Z-score is (90-60) / 15 which equals 2. Again, this means you scored 2 standard deviations above the mean on exam 2. Because your Z-score for both exams is the same, you did the same on both exams.
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A sample of 100 cars driving on a freeway during a morning commute was drawn, and the number of occupants in each car was recorded. The results were as follows: NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part.
Occupants 1 2 3 4 5
Number of Cars 71 16 8 3 2
a. For what proportion of cars was the number of occupants more than one standard deviation greater than the mean? (Round the final answer to two decimal places.)
Answer: 29%
Step-by-step explanation:
I considered the question to be: for what proportion of cars was the number of occupants more than 1 standard deviation and greater than the mean.
The first step is to calculate the weighted mean of the number of occupants in the cars. The next step is to determine the standard deviation using the formula √[ Σ ( xi - μ )² / N ]. Subsequently, identify the number of occupants that are more than one standard deviation greater than the mean.
Explanation:In this question, we're asked to calculate the proportion of cars that had more than one standard deviation above the mean number of occupants. First, we need to calculate the weighted mean (average) of the number of occupants in the cars. Based on the data, the mean can be calculated as:
Mean = (1*71 + 2*16 + 3*8 + 4*3 + 5*2) / 100 = 1.66
Next, we find the standard deviation. The standard deviation tells us how spread out the numbers are from the mean. Calculating standard deviation is a bit involved. The formula is √[ Σ ( xi - μ )² / N ]. Once you have these, look at the number of occupants that are more than one standard deviation greater than this mean.
Note: This is a statistical analysis question that requires knowledge of the concepts of mean and standard deviation.
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Euclidean distance can be used to calculate the dissimilarity between two observations. Let u = (25, $350) correspond to a 25-year-old customer that spent $350 at Store A in the previous fiscal year. Let v = (53, $420) correspond to a 53-year-old customer that spent $4,100 at Store A in the previous fiscal year. Calculate the dissimilarity between these two observations using Euclidean distance.
a. 66.21
b. 88.57
c. 72.28
d. 75.39
Answer:
Option D
75.39
Step-by-step explanation:
When provided with the co-ordinates (x, y) and(a, b) then the distance between them is given by [tex]\sqrt {(x-a)^{2}+(y-b)^{2}}[/tex]
Since u = (25, $350) and v = (53, $420) then the Euclidean distance will be
[tex]\sqrt {(53-25)^{2}+(350-420)^{2}}=75.3923073\approx 75.39[/tex]
The dissimilarity between the two observations using Euclidean distance is approximately 75.39(Option d).
Explanation:To calculate the dissimilarity between two observations using Euclidean distance, we need to find the distance between the corresponding elements in the two observations and then calculate the square root of the sum of their squared differences.
In this case, we have:
u = (25, $350) and v = (53, $420)
The distance between the ages is 53 - 25 = 28.
The distance between the amounts spent is $420 - $350 = $70.
Now we can use the formula for Euclidean distance:
Distance = sqrt((28)^2 + (70)^2) = sqrt(784 + 4900) = sqrt(5684) ≈ 75.39
Therefore, the dissimilarity between the two observations using Euclidean distance is approximately 75.39.
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Find the probability for the experiment of drawing two marbles (without replacement) at random from a bag containing one green, two yellow, and three red marbles.
1. Both marbles are red.
2. Both marbles are yellow.
3. Neither marble is yellow.
4. The marbles are of different colors.
Final answer:
To find the probability of drawing two marbles without replacement, calculate the probability of each event separately and multiply them together.
Explanation:
To find the probability of drawing two marbles without replacement, we need to calculate the number of favorable outcomes and divide it by the total number of possible outcomes.
1. Both marbles are red:
First, we calculate the probability of drawing a red marble on the first draw (3 red marbles out of 6 total marbles). Then, we calculate the probability of drawing a red marble on the second draw, given that the first marble drawn was red (2 red marbles out of 5 total marbles remaining). The probability is (3/6) * (2/5) = 1/5.
2. Both marbles are yellow:
First, we calculate the probability of drawing a yellow marble on the first draw (2 yellow marbles out of 6 total marbles). Then, we calculate the probability of drawing a yellow marble on the second draw, given that the first marble drawn was yellow (1 yellow marble out of 5 total marbles remaining). The probability is (2/6) * (1/5) = 1/15.
Guessing Answers Standard tests, such as the SAT, ACT, or Medical College Admission Test (MCAT), typically use multiple choice questions, each with five possible answers (a, b, c, d, e), one of which is correct. Assume that you guess the answers to the first three questions. a. Use the multiplication rule to find the probability that the first two guesses are wrong and the third is correct. That is, find P(WWC), where W denotes a wrong answer and C denotes a correct answer. b. Beginning with WWC, make a complete list of the different possible arrangements of two wrong answers and one correct answer, then find the probability for each entry in the list. c. Based on the preceding results, what is the probability of getting exactly one correct answer when the guesses are made?
Answer:
a) Probability of picking the first two answers wrong & the third answer correctly in that order, P(WWC) = 0.128
b) All possible outcomes = WWC, WCW, CWW
P(WWC) = 0.128; P(WCW) = 0.128; P(CWW) = 0.128
c) Total Probability of picking only one correct answer and two incorrect answers from the first three attempts = 0.384
Step-by-step explanation:
P(Correct answer) = P(C) = number of correct options/total options available.
That is, P(C) = 1/5 = 0.2
P(Wrong answer) = P(W) = 1 - 0.2 = 0.8 or (number of wrong options)/(total options available) = 4/5 = 0.8
a) Using the multiple rule for independent events,
P(WWC) = P(W) × P(W) × P(C) = 0.8 × 0.8 × 0.2 = 0.128
Probability of picking the first two answers wrong & the third answer correctly in that order = 0.128
b) All possible outcomes of picking two wrong answers and one right answer in whichever order for the first 3 questions are (WWC, WCW, CWW)
P(WWC) = P(W) × P(W) × P(C) = 0.8 × 0.8 × 0.2 = 0.128
P(WCW) = P(W) × P(C) × P(W) = 0.8 × 0.2 × 0.8 = 0.128
P(CWW) = P(C) × P(W) × P(W) = 0.2 × 0.8 × 0.8 = 0.128
c) Using the addition rule for disjoint events,
Total Probability of picking only one correct answer and two incorrect answers from the first three attempts = P(WWC) + P(WCW) + P(CWW) = 0.128 + 0.128 + 0.128 = 0.384
QED!
The probability of getting exactly one correct answer when guessing on three multiple-choice questions with five possible answers each is [tex]\(\frac{3}{25}\)[/tex].
a. To find the probability that the first two guesses are wrong and the third is correct, denoted as P(WWC), we use the multiplication rule for independent events. Since there are five possible answers for each question and only one correct answer, the probability of guessing wrong on one question is [tex]\(\frac{4}{5}\)[/tex] and the probability of guessing correctly is [tex]\(\frac{1}{5}\)[/tex]. Therefore, the probability of WWC is:
[tex]\[ P(WWC) = P(W) \times P(W) \times P(C) = \left(\frac{4}{5}\right) \times \left(\frac{4}{5}\right) \times \left(\frac{1}{5}\right) = \frac{16}{125} \][/tex]
b. The different possible arrangements of two wrong answers and one correct answer (WWC) are:
1. WWC
2. WWC
3. CWW
4. CW
5. WCW
6. WCW
For each of these arrangements, the probability is the same as calculated in part (a), which is \(\frac{16}{125}\).
c. Since there are six different ways to arrange two wrong answers and one correct answer, and each of these arrangements has the same probability, we multiply the probability of one such arrangement by the number of arrangements to find the total probability of getting exactly one correct
[tex]\[ P(\text{exactly one correct answer}) = 6 \times P(WWC) = 6 \times \frac{16}{125} = \frac{96}{125} \][/tex]
However, we must note that we have counted each arrangement twice because the order of the wrong answers (W) does not matter. Therefore, we need to divide the total by 2 to get the correct probability:
[tex]\[ P(\text{exactly one correct answer}) = \frac{96}{2 \times 125} = \frac{48}{125} \][/tex]
Upon reviewing the calculations, it appears there was an error in the final step. We should not divide by 2 because the arrangements are distinct due to the position of the correct answer (C). The correct total probability is indeed [tex]\(\frac{96}{125}\)[/tex], but since we are looking for the probability of exactly one correct answer, we have to consider that there are three questions and the correct answer could be on any of them. Therefore, we have already accounted for all possible arrangements by multiplying by 6.
The correct probability of getting exactly one correct answer when guessing on three multiple-choice questions is:
[tex]\[ P(\text{exactly one correct answer}) = \frac{96}{125} \][/tex]
However, this is not the final answer. We need to consider that there are three different ways to get exactly one correct answer out of three questions (CWW, WCW, WWC). Since these are mutually exclusive events, we add their probabilities:
[tex]\[ P(\text{exactly one correct answer}) = P(CWW) + P(WCW) + P(WWC) \][/tex]
[tex]\[ P(\text{exactly one correct answer}) = \frac{16}{125} + \frac{16}{125} + \frac{16}{125} \][/tex]
[tex]\[ P(\text{exactly one correct answer}) = 3 \times \frac{16}{125} \][/tex]
[tex]\[ P(\text{exactly one correct answer}) = \frac{48}{125} \][/tex]
Thus, the final correct probability is [tex]\(\frac{48}{125}\)[/tex], which simplifies to [tex]\(\frac{3}{25}\)[/tex].
Let M = {Λ,abb} and L = {bba,ab, a}, what is ML ? ML ={bba, abbbba,abbab,abbba, ab,a} ML ={bba, abbbba,abbab,abba, ab,a} ML ={bbab, abbbba,abbab,abba, ab,a} ML ={ba, abbbba,abbab,abba, ab,a}
Answer:
ML = {bba, ab, a, bbaabb, ababb, aabb}
Step-by-step explanation:
By application of Union of a set.
M = {bba,ab, a}
L = {Λ,abb}
ML = {bba, ab, a, bbaabb, ababb, aabb}
If a confidence interval is given from 45.82 up to 55.90 and the mean is known to be 50.86, what is the margin of error?
Answer:
[tex] ME = \frac{10.08}{2}= 5.04[/tex]
Step-by-step explanation:
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=50.86[/tex] represent the sample mean
[tex]\mu[/tex] population mean
s represent the sample standard deviation
n represent the sample size
Solution to the problem
The confidence interval for the mean is given by the following formula:
[tex] \bar X \pm ME[/tex] (1)
Or equivalently:
[tex]\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex] (2)
Where the margin of error is given by:
[tex] ME= t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex]
For this case we have the confidence interval limits given (45.82, 55.90)
We can find the width of the interval like this:
[tex] Width =55.90-45.82= 10.08[/tex]
And now the margin of error would be the half of the width since we assume that the confidence interval is symmetrical.
[tex] ME = \frac{10.08}{2}= 5.04[/tex]
Find M. Write your answer in simplest radical
Answer:
(√6/√2)ft
Step-by-step explanation:
cos 45 = m / √6 ft
m = cos 45 x √6 ft
m = (1 / √2) x √6 ft = (√6/√2)ft
The time taken for a computer to boot up, X, follows a normal distribution with mean 30 seconds and standard deviation 5 seconds. What is the probability that a computer will take more than 42 seconds to boot up?
Answer:
0.008 is the probability that a computer will take more than 42 seconds to boot up.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 30 seconds
Standard Deviation, σ = 5 second
We are given that the distribution of time taken for a computer to boot up is a bell shaped distribution that is a normal distribution.
Formula:
[tex]z_{score} = \displaystyle\frac{x-\mu}{\sigma}[/tex]
a) P(computer will take more than 42 seconds to boot up)
P(x > 42)
[tex]P( x > 42) = P( z > \displaystyle\frac{42 - 30}{5}) = P(z > 2.4)[/tex]
[tex]= 1 - P(z \leq 2.4)[/tex]
Calculation the value from standard normal z table, we have,
[tex]P(x > 42) = 1 - 0.992 = 0.008[/tex]
0.008 is the probability that a computer will take more than 42 seconds to boot up.