Question 1

The symbol used for the variance of the population is

Accepted Answer

A)   σ.
B)   σ2.
C)   s.
D)   s2.E) B) and C)
F) All of the above

Question 2

To avoid the problem of not having access to tables of the F distribution when a one-tailed test is required and with F values given for the lower tail, let​ the

Accepted Answer

A)   smaller sample variance be the numerator of the test statistic.
B)   larger sample variance be the numerator of the test statistic.
C)   sample variance from the population with the smaller hypothesized variance be the numerator of the test statistic.
D)   sample variance from the population with the larger hypothesized variance be the numerator of the test statistic.E) A) and B)
F) C) and D)

Question 3

What is the 90% confidence interval estimate of a population standard deviation when a sample
variance of 50 is obtained from a sample of 15 items?

Accepted Answer

The answer of What is the 90% confidence interval estimate...

Question 4

The 95% confidence interval estimate of a population variance when a sample variance of 324 is obtained from a sample of 81 items is

Accepted Answer

A)   14.14 to 174.94.
B)   243.086 to 453.520.
C)   16.42 to 194.35.
D)   254.419 to 429.203.E) A) and B)
F) A) and C)

Question 5

A random sample of 22 employees of a local utility firm showed that their monthly incomes had a sample standard deviation of $110.Provide a 90% confidence interval estimate for the standard deviation of the incomes of all employees of the firm.

Accepted Answer

The answer of A random sample of 22 employees of...

Question 6

The symbol used for the variance of the sample is

Accepted Answer

A)   σ.
B)   σ2.
C)   s.
D)   s2.E) A) and D)
F) A) and B)

Question 7

A sample of 21 elements is selected to estimate a 90% confidence interval for the variance of the population.The chi-square value(s)  to be used for this interval estimation is(are)

Accepted Answer

A)   31.410.
B)   12.443.
C)   10.851 and 31.410.
D)   12.443 and 28.412.E) C) and D)
F) B) and D)

Question 8

To avoid the problem of not having access to Tables of F distribution when F values are needed for the lower tail, the numerator of the test statistic for a two-tailed test should be the one with

Accepted Answer

A)   the larger sample size.
B)   the smaller sample size.
C)   the larger sample variance.
D)   the smaller sample variance.E) A) and B)
F) A) and C)

Question 9

​Consider the following hypothesis problem. n = 30
H0: σ2 = 500
S2 = 625
Ha: σ2 ≠ 500
​
At the 5% level of significance, the null hypothesis

Accepted Answer

A)   ​should be rejected.
B)   ​should not be rejected.
C)   ​should be revised.
D)   should not be tested.E) B) and C)
F) A) and B)

Question 10

A sample of 61 observations yielded a sample standard deviation of 6.If we want to test H0: σ2 = 40, the test statistic is

Accepted Answer

A)   54.
B)   9.15.
C)   54.90.
D)   9.E) A) and C)
F) None of the above

Question 11

The manager of the service department of a local car dealership has noted that the service times of a sample of 16 new automobiles has a standard deviation of 5 minutes.A 95% confidence interval estimate for the variance of service times for all their new automobiles is

Accepted Answer

A)   13.642 to 59.885.
B)   9.46 to 34.09.
C)   2.144 to 9.948.
D)   2.728 to 11.977.E) C) and D)
F) None of the above

Question 12

A sample of 30 items provided a sample mean of 28 and a sample standard deviation of 6.Test the following hypotheses using α = .05.What is your conclusion?
H0: σ2 ≤ 25
Ha: σ2 > 25

Accepted Answer

χ²= 41.76 < 42.557; do not re...

Question 13

Consider the following hypothesis problem. ​
N = 23
S2 = 60
H0: σ2 ≤ 66
Ha: σ2 > 66
​
If the test is to be performed at the .05 level of significance, the null hypothesis

Accepted Answer

A)   should be rejected.
B)   should not be rejected.
C)   should be revised.
D)   should not be tested.E) None of the above
F) A) and B)

Question 14

A sample of 22 bottles of soft drink showed a variance of .64 in their contents.At the 5% level, determine whether or not the standard deviation of the population is significantly different from .7 ounces.Use the critical value approach.

Accepted Answer

H₀: σ² = .49
H_a: σ² ≠ ...

Question 15

Based on the sample evidence below, we want to test the hypothesis that population A has a larger variance than population B. ​
Sample A
Sample B
N
11
10
S2
12) 1
5
​
The p-value is approximately

Accepted Answer

A)   .10.
B)   .05.
C)   .025.
D)   .01.E) A) and B)
F) A) and C)

Question 16

The contents of a sample of 26 cans of apple juice showed a standard deviation of .06 ounces.We are interested in testing whether the variance of the population is significantly more than .003.The null hypothesis is

Accepted Answer

A)   s2 > .003.
B)   s2 ≤ .003.
C)   σ2 > .003.
D)   σ2 ≤ .003.E) None of the above
F) A) and C)

Question 17

A sample of 61 elements is selected to estimate a 95% confidence interval for the variance of the population.The chi-square values to be used for this interval estimation are

Accepted Answer

A)   40.482 and 83.298.
B)   32.357 and 71.420.
C)   34.764 and 67.505.
D)   43.188 and 79.082.E) A) and B)
F) B) and D)

Question 18

The sampling distribution used when making inferences about a single population's variance is

Accepted Answer

A)   an F distribution.
B)   a t distribution.
C)   a chi-square distribution.
D)   a normal distribution.E) A) and B)
F) A) and C)

Question 19

A random sample of 20 observations showed a standard deviation of 8.At a .05 level of significance, test to see if the variance of the population is significantly less than 65.Use the critical value approach.

Accepted Answer

H₀: σ² ≥ 65
H_a: σ² < 65
...

Question 20

The average score of a sample of 30 students on their second statistics examination was 85 with a standard deviation of 11.Is the variance of the population significantly more than 80? Use a .05 level of significance.

Accepted Answer

H₀: σ² ≤ 80
H_a: σ² > 80
chi-squa...

Exam 11: Inferences About Population Variances

​Consider the following hypothesis problem. n = 30 H0: σ2 = 500 S2 = 625 Ha: σ2 ≠ 500 ​ At the 5% level of significance, the null hypothesis

Correct AnswerverifiedShow Answer

Consider the following hypothesis problem. ​ N = 23 S2 = 60 H0: σ2 ≤ 66 Ha: σ2 > 66 ​ If the test is to be performed at the .05 level of significance, the null hypothesis

Correct AnswerverifiedShow Answer

A random sample of 20 observations showed a standard deviation of 8.At a .05 level of significance, test to see if the variance of the population is significantly less than 65.Use the critical value approach.

Correct AnswerverifiedH0: σ2 ≥ 65Ha: σ2 < 65...View AnswerShow Answer

The symbol used for the variance of the population is

Correct AnswerverifiedShow Answer

A random sample of 22 employees of a local utility firm showed that their monthly incomes had a sample standard deviation of $110.Provide a 90% confidence interval estimate for the standard deviation of the incomes of all employees of the firm.

Correct AnswerverifiedShow Answer

The average score of a sample of 30 students on their second statistics examination was 85 with a standard deviation of 11.Is the variance of the population significantly more than 80? Use a .05 level of significance.

Correct Answerverified​H0: σ2 ≤ 80Ha: σ2 > 80chi-squa...View AnswerShow Answer

Based on the sample evidence below, we want to test the hypothesis that population A has a larger variance than population B. ​ Sample A Sample B N 11 10 S2 12) 1 5 ​ The p-value is approximately

Correct AnswerverifiedShow Answer

The contents of a sample of 26 cans of apple juice showed a standard deviation of .06 ounces.We are interested in testing whether the variance of the population is significantly more than .003.The null hypothesis is

Correct AnswerverifiedShow Answer

A sample of 30 items provided a sample mean of 28 and a sample standard deviation of 6.Test the following hypotheses using α = .05.What is your conclusion? H0: σ2 ≤ 25 Ha: σ2 > 25

Correct Answerverified​χ2 = 41.76 < 42.557; do not re...View AnswerShow Answer

The sampling distribution used when making inferences about a single population's variance is

Correct AnswerverifiedShow Answer

A sample of 61 observations yielded a sample standard deviation of 6.If we want to test H0: σ2 = 40, the test statistic is

Correct AnswerverifiedShow Answer

To avoid the problem of not having access to tables of the F distribution when a one-tailed test is required and with F values given for the lower tail, let​ the

Correct AnswerverifiedShow Answer

A sample of 22 bottles of soft drink showed a variance of .64 in their contents.At the 5% level, determine whether or not the standard deviation of the population is significantly different from .7 ounces.Use the critical value approach.

Correct Answerverified​H0: σ2 = .49Ha: σ2 ≠ ...View AnswerShow Answer

A sample of 21 elements is selected to estimate a 90% confidence interval for the variance of the population.The chi-square value(s) to be used for this interval estimation is(are)

Correct AnswerverifiedShow Answer

The manager of the service department of a local car dealership has noted that the service times of a sample of 16 new automobiles has a standard deviation of 5 minutes.A 95% confidence interval estimate for the variance of service times for all their new automobiles is

Correct AnswerverifiedShow Answer

The 95% confidence interval estimate of a population variance when a sample variance of 324 is obtained from a sample of 81 items is

Correct AnswerverifiedShow Answer

A sample of 61 elements is selected to estimate a 95% confidence interval for the variance of the population.The chi-square values to be used for this interval estimation are

Correct AnswerverifiedShow Answer

The symbol used for the variance of the sample is

Correct AnswerverifiedShow Answer

To avoid the problem of not having access to Tables of F distribution when F values are needed for the lower tail, the numerator of the test statistic for a two-tailed test should be the one with

Correct AnswerverifiedShow Answer

What is the 90% confidence interval estimate of a population standard deviation when a sample variance of 50 is obtained from a sample of 15 items?

Correct AnswerverifiedShow Answer

Consider the following hypothesis problem. n = 30 H₀: σ² = 500 S² = 625 H_a: σ² ≠ 500 At the 5% level of significance, the null hypothesis

Correct Answer
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Consider the following hypothesis problem. N = 23 S² = 60 H₀: σ² ≤ 66 H_a: σ² > 66 If the test is to be performed at the .05 level of significance, the null hypothesis

Correct Answer
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H₀: σ² ≥ 65
H_a: σ² < 65
...
View Answer

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H₀: σ² ≤ 80
H_a: σ² > 80
chi-squa...
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Based on the sample evidence below, we want to test the hypothesis that population A has a larger variance than population B. Sample A Sample B N 11 10 S² 12) 1 5 The p-value is approximately

Correct Answer
verified

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A sample of 30 items provided a sample mean of 28 and a sample standard deviation of 6.Test the following hypotheses using α = .05.What is your conclusion? H₀: σ² ≤ 25 H_a: σ² > 25

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χ²= 41.76 < 42.557; do not re...
View Answer

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A sample of 61 observations yielded a sample standard deviation of 6.If we want to test H₀: σ² = 40, the test statistic is

Correct Answer
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To avoid the problem of not having access to tables of the F distribution when a one-tailed test is required and with F values given for the lower tail, let the

Correct Answer
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Correct Answer
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H₀: σ² = .49
H_a: σ² ≠ ...
View Answer

Correct Answer
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