Question 1

In testing the difference between two population variances,it is a common practice to compute the F statistic so that its value is always greater than or equal to one.

Accepted Answer

A) True 
 B)False

Question 2

The mid-distance running coach,Zdravko Popovich,for the Olympic team of an eastern European country claims that his six-month training program significantly reduces the average time to complete a 1500-meter run.Five mid-distance runners were randomly selected before they were trained with coach Popovich's six-month training program and their completion time of 1500-meter run was recorded (in minutes).After six months of training under coach Popovich,the same five runners' 1500 meter run time was recorded again the results are given below.  Construct the appropriate 95% confidence interval.(sd = .228)

Accepted Answer

A) (0.063 0.497) 
B) (-0.206 0.766) 
C) (-0.003 0.563) 
D) (0.018 0.542)

Question 3

When comparing the variances of two normally distributed populations using independent random samples,the correct test statistic to use is __________.

Accepted Answer

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

Question 4

When comparing the variances of two normally distributed populations using independent random samples,if  ,the calculated value of F will always be equal to one.

Accepted Answer

A) True 
 B)False

Question 5

In forming a confidence interval for  ,only two assumptions are required: independent samples and sample sizes of at least 30.

Accepted Answer

A) True 
 B)False

Question 6

Find a 90 percent confidence interval for the difference between the proportions of Group l and Group 2.Let p1 represent the population proportion of the people in group 1 who are in favor of new packaging and Let p2 represent the population proportion of the people in group 2 who are in favor of new packaging,where  1 = .21,  2 = .13,n1= 300,n2 = 400.

Accepted Answer

A) (.0472 .1128) 
B) (.0510 .1090) 
C) (.0232 .1368) 
D) (.0324 .1276)

Question 7

When we test H0: µ1- µ2 $\le$0,HA: µ1- µ2> 0,  1 = 15.4,  2 = 14.5,$\sigma$1 = 2,$\sigma$2 = 2.28,n1 = 35,n2 = 18 at $\alpha$ = .01,the test statistic used is:

Accepted Answer

A) 1.42 
B) 2.10 
C) 2.33 
D) 21.6

Question 8

Find a 95 percent confidence interval for the difference between means where n1 = 50,n2= 36,  1 = 80,  2 = 75,$\sigma$12 = 5 and $\sigma$22 = 3.

Accepted Answer

A) (4.16 5.84) 
B) (3.30 6.70) 
C) (4.40 5.60) 
D) (4.64 5.36)

Question 9

When testing a hypothesis about the mean of a 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) Chi-square 
E) None of the above

Question 10

Find a 95 percent confidence interval for µ1- µ2,where n1= 9,n2 = 6,  1 = 64,  2 = 59,s12 = 6 and s22 = 3.(Assume equal population variances)

Accepted Answer

A) (2.357 7.643) 
B) (2.494 7.506) 
C) (2.528 7.472) 
D) (3.840 6.160)

Question 11

When comparing two independent population means when population variances are not known and the samples are normally distributed,the correct test statistic to use is ____.

Accepted Answer

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

Question 12

Find a 99 percent confidence interval for the difference between means n1 = 49,n2 = 49,  1 = 87,  2 = 92, $\sigma$12 = 13 and  $\sigma$22 = 15.

Accepted Answer

A) (-12.30 2.30) 
B) (-6.47 -3.53) 
C) (-6.94 -3.05) 
D) (-5.57 -4.43)

Question 13

A coffee shop franchise owner is looking at two possible locations for a new shop.To help make a decision he looks at the number of pedestrians that go by each of the two locations in one-hour segments.At location A,counts are taken for 35 one-hour units and with a mean number of pedestrians of 421 and a sample standard deviation of 122.At the second location (B),counts are taken for 50 one hour units with a mean number of pedestrians of 347 and a sample standard deviation of 85.Assume the two populations variances are not known but are equal.Calculate the pooled estimate of  .

Accepted Answer

A) 10362.42 
B) 101.80 
C) 22.40 
D) 503.32

Question 14

A marketing research company surveyed grocery shoppers in the east and west coasts to see the percentage of the customers who prefer chicken to other meat.The data are given below.  What is the test statistic for this hypothesis test?

Accepted Answer

A) 1.645 
B) 3.92 
C) 1.96 
D) 3.09

Question 15

An experiment in which two different measurements are taken on the same units and inferences are made using the differences between the pairs of measurements is a(n)______ experiment.

Accepted Answer

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

Question 16

What is the value of the F-statistic for H0:  $\sigma$12 $\le$ $\sigma$12,HA:  $\sigma$12>  $\sigma$12,where s1= 3.3,and s2 = 2.1.

Accepted Answer

A) 2.47 
B) 1.57 
C) 6.48 
D) 6.10

Question 17

If we are testing the hypothesis about the mean of a population of paired differences with samples of n1 = 10,n2 = 10,the degrees of freedom for the t statistic is ____.

Accepted Answer

A) 20 
B) 9 
C) 18 
D) 10

Question 18

Find a 95 percent confidence interval for the difference between the proportions of older and younger drivers who have tickets where  1 = .275,  2 = .25,n1= 1000,n2 = 1000.

Accepted Answer

A) (-.007 .057) 
B) (.024 .026) 
C) (-.002 .052) 
D) (-.014 .064)

Question 19

In testing the difference between two independent population means if the variances of the two populations are not equal the critical value of the t statistic is obtained by calculating ___________________.

Accepted Answer

A) degrees of freedom 
B) the sum of the two sample sizes (n1 + n2) 
C) p-value 
D) pooled variance

Question 20

In an opinion survey,a random sample of 1000 adults from the U.S.A and 1000 adults from Germany were asked whether they supported the death penalty.590 American adults and 560 German adults indicated that they supported the death penalty.The researcher wants to know if there is sufficient evidence to conclude that the proportion of adults who support the death penalty is higher in the U.S.A.than in Germany.What is the decision at  = .10?

Accepted Answer

A) Reject the null hypothesis 
B) Can't reject the null hypothesis

Exam 10: Statistical Inferences Based on Two Samples

In testing the difference between two population variances,it is a common practice to compute the F statistic so that its value is always greater than or equal to one.

When comparing the variances of two normally distributed populations using independent random samples,the correct test statistic to use is __________.

When comparing the variances of two normally distributed populations using independent random samples,if ,the calculated value of F will always be equal to one.

In forming a confidence interval for ,only two assumptions are required: independent samples and sample sizes of at least 30.

When testing a hypothesis about the mean of a population of paired differences in which two different observations are taken on the same units,the correct test statistic to use is:

Find a 95 percent confidence interval for µ₁- µ₂,where n₁= 9,n₂ = 6, ₁ = 64, ₂ = 59,s₁² = 6 and s₂² = 3.(Assume equal population variances)

When comparing two independent population means when population variances are not known and the samples are normally distributed,the correct test statistic to use is ____.

A marketing research company surveyed grocery shoppers in the east and west coasts to see the percentage of the customers who prefer chicken to other meat.The data are given below. What is the test statistic for this hypothesis test?

An experiment in which two different measurements are taken on the same units and inferences are made using the differences between the pairs of measurements is a(n) ______ experiment.

What is the value of the F-statistic for H₀: $\sigma$ ₁² $\le$ $\sigma$ ₁²,H_A: $\sigma$ ₁²> $\sigma$ ₁²,where s₁= 3.3,and s₂ = 2.1.

If we are testing the hypothesis about the mean of a population of paired differences with samples of n₁ = 10,n₂ = 10,the degrees of freedom for the t statistic is ____.

Find a 95 percent confidence interval for the difference between the proportions of older and younger drivers who have tickets where ₁ = .275, ₂ = .25,n₁= 1000,n₂ = 1000.

In testing the difference between two independent population means if the variances of the two populations are not equal the critical value of the t statistic is obtained by calculating ___________________.

Exam 10: Statistical Inferences Based on Two Samples

In testing the difference between two population variances,it is a common practice to compute the F statistic so that its value is always greater than or equal to one.

When comparing the variances of two normally distributed populations using independent random samples,the correct test statistic to use is __________.

When comparing the variances of two normally distributed populations using independent random samples,if ,the calculated value of F will always be equal to one.

In forming a confidence interval for ,only two assumptions are required: independent samples and sample sizes of at least 30.

When we test H0: µ1- µ2 ≤\le≤ 0,HA: µ1- µ2> 0, 1 = 15.4, 2 = 14.5, σ\sigmaσ 1 = 2, σ\sigmaσ 2 = 2.28,n1 = 35,n2 = 18 at α\alphaα = .01,the test statistic used is:

Find a 95 percent confidence interval for the difference between means where n1 = 50,n2= 36, 1 = 80, 2 = 75, σ\sigmaσ 12 = 5 and σ\sigmaσ 22 = 3.

When testing a hypothesis about the mean of a population of paired differences in which two different observations are taken on the same units,the correct test statistic to use is:

Find a 95 percent confidence interval for µ1- µ2,where n1= 9,n2 = 6, 1 = 64, 2 = 59,s12 = 6 and s22 = 3.(Assume equal population variances)

When comparing two independent population means when population variances are not known and the samples are normally distributed,the correct test statistic to use is ____.

Find a 99 percent confidence interval for the difference between means n1 = 49,n2 = 49, 1 = 87, 2 = 92, σ\sigmaσ 12 = 13 and σ\sigmaσ 22 = 15.

A marketing research company surveyed grocery shoppers in the east and west coasts to see the percentage of the customers who prefer chicken to other meat.The data are given below. What is the test statistic for this hypothesis test?

An experiment in which two different measurements are taken on the same units and inferences are made using the differences between the pairs of measurements is a(n) ______ experiment.

What is the value of the F-statistic for H0: σ\sigmaσ 12 ≤\le≤ σ\sigmaσ 12,HA: σ\sigmaσ 12> σ\sigmaσ 12,where s1= 3.3,and s2 = 2.1.

If we are testing the hypothesis about the mean of a population of paired differences with samples of n1 = 10,n2 = 10,the degrees of freedom for the t statistic is ____.

Find a 95 percent confidence interval for the difference between the proportions of older and younger drivers who have tickets where 1 = .275, 2 = .25,n1= 1000,n2 = 1000.

In testing the difference between two independent population means if the variances of the two populations are not equal the critical value of the t statistic is obtained by calculating ___________________.

Find a 95 percent confidence interval for µ₁- µ₂,where n₁= 9,n₂ = 6, ₁ = 64, ₂ = 59,s₁² = 6 and s₂² = 3.(Assume equal population variances)

What is the value of the F-statistic for H₀: $\sigma$ ₁² $\le$ $\sigma$ ₁²,H_A: $\sigma$ ₁²> $\sigma$ ₁²,where s₁= 3.3,and s₂ = 2.1.

If we are testing the hypothesis about the mean of a population of paired differences with samples of n₁ = 10,n₂ = 10,the degrees of freedom for the t statistic is ____.

Find a 95 percent confidence interval for the difference between the proportions of older and younger drivers who have tickets where ₁ = .275, ₂ = .25,n₁= 1000,n₂ = 1000.