Question 1

A test of spelling ability is given to a random sample of 10 students before and after they completed a spelling course.The mean score before the course was 119.60 and after the course the mean score was 130.80.The standard deviation of the difference was 16.061.Calculate the test statistic to test the claim.

Accepted Answer

A) 2.21 
B) 0.697 
C) 2.09 
D) 6.97

Question 2

When testing the difference between two population proportions using large independent random samples,__________ test statistic is used.

Accepted Answer

A) Z 
B) t 
C) F 
D) Chi-square 
E) None of the above

Question 3

An independent samples experiment is an experiment in which there is no relationship between the measurements in the different samples.

Accepted Answer

A) True 
 B)False

Question 4

The test of means for two related populations match the observations (matched pairs)in order to reduce the ________________ attributable to the difference between individual observations and other factors.

Accepted Answer

A) means 
B) test statistic 
C) degrees of freedom 
D) variation

Question 5

In testing the difference between the means of two normally distributed populations using large independent random samples,the sample sizes from the two populations must be equal in order to use a Z statistic.

Accepted Answer

A) True 
 B)False

Question 6

An experiment in which there is no relationship between the measurements on the different samples is a(n)______ experiment.

Accepted Answer

A) Paired difference 
B) Equal variances 
C) Independent samples 
D) Dependent samples

Question 7

If the limits of the confidence interval of the difference between the means of two normally distributed populations were 8.5 and 11.5 at the 95% confidence level,then we can conclude that we are 95% certain that there is a significant difference between the two population means.

Accepted Answer

A) True 
 B)False

Question 8

Use the following data and a test of the equality of variances for two populations at $\alpha$ = .10,where sample 1 is randomly selected from population 1 and sample 2 is randomly selected from population 2.Identify the critical value used for testing the equality of the variances.

Accepted Answer

A) 1.138 
B) 1.645 
C) 5.05 
D) 6.39

Question 9

Given the following information about a hypothesis test of the difference between two variances based on independent random samples,what is the critical value of the test statistic at a significance level of .05? Assume that the samples are obtained from normally distributed populations. HA:  $\sigma$2A>  $\sigma$2B,  1 = 12,  2 = 9,s1 = 5,s2 = 3,n1 = 13,n2 = 10.

Accepted Answer

A) 3.87 
B) 3.44 
C) 3.07 
D) 2.8 
E) 2.38

Question 10

If the limits of the confidence interval of the difference between the means of two normally distributed populations were from -2.6 and 1.4 at the 95% confidence level,then we can conclude that we are 95% certain that there is a significant difference between the two population means.

Accepted Answer

A) True 
 B)False

Question 11

The registrar at a state college is interested in determining whether there is a difference of more than one credit hour between male and female students in the average number of credit hours taken during a term.She selected a random sample of 60 male and 60 female students and observed the following sample information.  Calculate the test statistic to be used in the analysis.

Accepted Answer

A) 5.67 
B) 2.05 
C) 1.73 
D) 6.71

Question 12

In comparing the difference between two independent population means,by using two small independent samples,the sampling distributions of the population means are at least approximately ________________.

Accepted Answer

A) skewed right 
B) skewed left 
C) normal 
D) binomial

Question 13

Suppose that a realtor is interested in comparing the price of midrange homes in two cities in a Midwestern state.She conducts a small survey in the two cities looking at the price of midrange homes.Assume equal population variances.  Calculate the 95% confidence interval where pooled variance = 4335357.143

Accepted Answer

A) (649.24 5150.76) 
B) (-1566.21 7366.21) 
C) (675.46 5124.54) 
D) (-766.67 6566.67)

Question 14

In testing the difference between the means of two normally distributed populations,if µ1 = µ2 = 50,n1= 9,n2 = 13,the degrees of freedom for the t statistic is ___________.

Accepted Answer

A) 22 
B) 21 
C) 19 
D) 20

Question 15

A fast food company uses two management-training methods.Method 1 is a traditional method of training and Method 2 is a new and innovative method.The company has just hired 31 new management trainees.15 of the trainees are randomly selected and assigned to the first method,and the remaining 16 trainees are assigned to the second training method.After three months of training,the management trainees took a standardized test.The test was designed to evaluate their performance and learning from training.The sample mean score and sample standard deviation of the two methods are given below.The management wants to determine if the company should implement the new training method.  What is the sample value of the test statistic? (Assume equal population variances)

Accepted Answer

A) -1.779 
B) -2.311 
C) -4.317 
D) -0.830

Question 16

When testing the difference for the population of paired differences in which two different observations are taken on the same units,the correct test statistic to use is ____.

Accepted Answer

A) Z 
B) t 
C) F 
D) t2

Question 17

Given the following information about a hypothesis test of the difference between two means based on independent random samples,which one of the following is the correct rejection region at a significance level of .05? HA: µA> µB,  1 = 12,  2 = 9,s1 = 4,s2 = 2,n1 = 13,n2 = 10.

Accepted Answer

A) Reject H0 if Z > 1.96 
B) Reject H0 if Z > 1.645 
C) Reject H0 if t > 1.721 
D) Reject H0 if t > 2.08 
E) Reject H0 if t > 1.782

Question 18

Assume that we are constructing confidence interval for the difference in the means of two populations based on independent random samples.If both sample sizes  and the distribution of both populations are highly skewed,then a confidence interval for the difference in the means can be constructed using the t test statistic.

Accepted Answer

A) True 
 B)False

Question 19

In which of the following tests is the variable of interest the difference between the values of the observations from the two samples rather than the actual observations themselves?

Accepted Answer

A) A test of hypothesis about the mean of a population of paired differences selected from two related samples. 
B) A test of hypothesis about the difference between the means of two normally distributed populations using large independent samples. 
C) A test of hypothesis about the difference between the means of two normally distributed populations using small independent samples. 
D) A test of hypothesis about the difference between two population proportions,using large independent random samples. 
E) A test of hypothesis about the difference between the variances of two normally distributed populations using independent samples.

Question 20

In testing the difference between two independent population means,it is assumed that the level of measurement is at least ______________.

Accepted Answer

A) a ratio variable 
B) a qualitative variable 
C) an interval variable 
D) a categorical variable

Exam 10: Statistical Inferences Based on Two Samples

When testing the difference between two population proportions using large independent random samples,__________ test statistic is used.

An independent samples experiment is an experiment in which there is no relationship between the measurements in the different samples.

The test of means for two related populations match the observations (matched pairs) in order to reduce the ________________ attributable to the difference between individual observations and other factors.

In testing the difference between the means of two normally distributed populations using large independent random samples,the sample sizes from the two populations must be equal in order to use a Z statistic.

An experiment in which there is no relationship between the measurements on the different samples is a(n) ______ experiment.

If the limits of the confidence interval of the difference between the means of two normally distributed populations were 8.5 and 11.5 at the 95% confidence level,then we can conclude that we are 95% certain that there is a significant difference between the two population means.

If the limits of the confidence interval of the difference between the means of two normally distributed populations were from -2.6 and 1.4 at the 95% confidence level,then we can conclude that we are 95% certain that there is a significant difference between the two population means.

In comparing the difference between two independent population means,by using two small independent samples,the sampling distributions of the population means are at least approximately ________________.

In testing the difference between the means of two normally distributed populations,if µ₁ = µ₂ = 50,n₁= 9,n₂ = 13,the degrees of freedom for the t statistic is ___________.

When testing the difference for the population of paired differences in which two different observations are taken on the same units,the correct test statistic to use is ____.

Given the following information about a hypothesis test of the difference between two means based on independent random samples,which one of the following is the correct rejection region at a significance level of .05? H_A: µ_A> µ_B, ₁ = 12, ₂ = 9,s₁ = 4,s₂ = 2,n₁ = 13,n₂ = 10.

In which of the following tests is the variable of interest the difference between the values of the observations from the two samples rather than the actual observations themselves?

In testing the difference between two independent population means,it is assumed that the level of measurement is at least ______________.

Exam 10: Statistical Inferences Based on Two Samples

When testing the difference between two population proportions using large independent random samples,__________ test statistic is used.

An independent samples experiment is an experiment in which there is no relationship between the measurements in the different samples.

The test of means for two related populations match the observations (matched pairs) in order to reduce the ________________ attributable to the difference between individual observations and other factors.

In testing the difference between the means of two normally distributed populations using large independent random samples,the sample sizes from the two populations must be equal in order to use a Z statistic.

An experiment in which there is no relationship between the measurements on the different samples is a(n) ______ experiment.

If the limits of the confidence interval of the difference between the means of two normally distributed populations were 8.5 and 11.5 at the 95% confidence level,then we can conclude that we are 95% certain that there is a significant difference between the two population means.

Use the following data and a test of the equality of variances for two populations at α\alphaα = .10,where sample 1 is randomly selected from population 1 and sample 2 is randomly selected from population 2.Identify the critical value used for testing the equality of the variances.

If the limits of the confidence interval of the difference between the means of two normally distributed populations were from -2.6 and 1.4 at the 95% confidence level,then we can conclude that we are 95% certain that there is a significant difference between the two population means.

In comparing the difference between two independent population means,by using two small independent samples,the sampling distributions of the population means are at least approximately ________________.

In testing the difference between the means of two normally distributed populations,if µ1 = µ2 = 50,n1= 9,n2 = 13,the degrees of freedom for the t statistic is ___________.

When testing the difference for the population of paired differences in which two different observations are taken on the same units,the correct test statistic to use is ____.

Given the following information about a hypothesis test of the difference between two means based on independent random samples,which one of the following is the correct rejection region at a significance level of .05? HA: µA> µB, 1 = 12, 2 = 9,s1 = 4,s2 = 2,n1 = 13,n2 = 10.

In which of the following tests is the variable of interest the difference between the values of the observations from the two samples rather than the actual observations themselves?

In testing the difference between two independent population means,it is assumed that the level of measurement is at least ______________.

In testing the difference between the means of two normally distributed populations,if µ₁ = µ₂ = 50,n₁= 9,n₂ = 13,the degrees of freedom for the t statistic is ___________.

Given the following information about a hypothesis test of the difference between two means based on independent random samples,which one of the following is the correct rejection region at a significance level of .05? H_A: µ_A> µ_B, ₁ = 12, ₂ = 9,s₁ = 4,s₂ = 2,n₁ = 13,n₂ = 10.