Deck 8: Estimation: Additional Topics

Question 1

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
Calculate the margin of error for the given data assuming 95% confidence level: n_x = 250
_x = 0.65 n_y = 360
_y = 0.78

A)0.085
B)1.05
C)0.052
D)0.072

Answer 1

0.072

Question 2

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
For constructing a 95% confidence interval estimate for the difference between the means of two normally distributed populations,where the unknown population variances are assumed not to be equal,the summary statistics computed from two independent samples are as follows:
n₁ = 50,
₁ = 175,s₁ = 18.5,n₂ = 42,
₂ = 158,and s₂ = 32.4
What is the upper confidence limit of the 95% confidence interval for the difference between the means?

A)19.123
B)28.279
C)24.911
D)5)788

Answer 2

28.279

Question 3

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Independent samples of math scores from students in the U.S.and Europe were collected from normal populations.A sample of 50 students from the U.S.had an average score of 570 while a sample of 50 European students had an average score of 540.The population standard deviations for the average scores of the US and European students are 102 and 115 respectively.
The confidence interval for the difference between two population means that are normally distributed where the population variances are unknown and are not assumed to be equal rely on the use of:

A)the average sample variance.
B)the estimated sample variance.
C)Satterthwaite's approximation.
D)the pooled variance.

Answer 3

Satterthwaite's approximation.

Question 4

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
The pooled variance is formed by combining information from two independent samples.
If
= 39,
= 25,and n₁ = n₂ = 12 then
Is equal to:

A)31
B)45
C)30
D)32

Question 5

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In a recent survey of 240 teachers in Richmond,Virginia,77.2% supported standardized national testing of elementary students.In a survey of 162 teachers in Raleigh,North Carolina,64.2% supported national testing.
What is the upper confidence limit of the 99% confidence interval for the difference between the two population proportions?

A)0.249
B)0.222
C)0.265
D)0.278

Question 6

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
Find the width of the 98% confidence interval.

A)5.46
B)3.64
C)0.91
D)0.60

Question 7

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
What is the upper confidence limit of the 98% confidence interval for the difference between the population means?

A)29.81
B)327.95
C)20.60
D)28.32

Question 8

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
For constructing a 95% confidence interval estimate for the difference between the means of two normally distributed populations,where the unknown population variances are assumed not to be equal,the summary statistics computed from two independent samples are as follows:
n₁ = 50,
₁ = 175,s₁ = 18.5,n₂ = 42,
₂ = 158,and s₂ = 32.4
What is the lower confidence limit of the 95% confidence interval for the difference between the means?

A)5.72
B)6.37
C)8.45
D)9.20

Question 9

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Independent samples of math scores from students in the U.S.and Europe were collected from normal populations.A sample of 50 students from the U.S.had an average score of 570 while a sample of 50 European students had an average score of 540.The population standard deviations for the average scores of the US and European students are 102 and 115 respectively.
What is the upper confidence limit of the 95% confidence interval for the difference between the population means?

A)65.65
B)51.73
C)72.61
D)94.23

Question 10

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A career counselor is interested in examining the salaries earned by graduate business school students at the end of the first year after graduation.In particular,the counselor is interested in seeing whether there is a difference between men and women graduates' salaries.From a random sample of 20 men,the mean salary is found to be $42,780 with a standard deviation of $5,426.From a sample of 12 women,the mean salary is found to be $40,136 with a standard deviation of $4,383.Assume that the random sample observations are from normally distributed populations,and that the population variances are assumed to be equal.
What is the lower confidence limit of the 95% confidence interval for the difference between the population mean salary for men and women?

A)-$1,135.781
B)-$791.792
C)-$952.833
D)$834.835

Question 11

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
Calculate the margin of error.

A)3.32
B)2.26
C)2.05
D)1.82

Question 12

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
n_x = 360,
_x = 0.69,n_y = 350,
_y = 0.76
What is the upper confidence limit of the 98% confidence interval for the difference in population proportions?

A)-0.0151
B)0.004
C)0.007
D)0.025

Question 13

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
A 95% confidence interval estimate for the difference between two population means,μ₁ - μ₂,is determined to be 62.75 < μ₁ - μ₂ < 68.52.Which of the following is true if the confidence level is reduced to 90%?

A)The confidence interval becomes wider.
B)The confidence interval remains the same.
C)The confidence interval becomes narrower.
D)More information is required to determine the answer.

Question 14

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In a recent survey of 240 teachers in Richmond,Virginia,77.2% supported standardized national testing of elementary students.In a survey of 162 teachers in Raleigh,North Carolina,64.2% supported national testing.
What is the lower confidence limit of the 99% confidence interval for the difference between the two population proportions?

A)-0.011
B)0.036
C)-0.036
D)0.011

Question 15

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A career counselor is interested in examining the salaries earned by graduate business school students at the end of the first year after graduation.In particular,the counselor is interested in seeing whether there is a difference between men and women graduates' salaries.From a random sample of 20 men,the mean salary is found to be $42,780 with a standard deviation of $5,426.From a sample of 12 women,the mean salary is found to be $40,136 with a standard deviation of $4,383.Assume that the random sample observations are from normally distributed populations,and that the population variances are assumed to be equal.
In order to construct a confidence interval estimate for the difference between two population means,independent samples are obtained from two normal populations with unknown but assumed to be equal variances.If the first sample contains 18 items and the second sample contains 14 items,which of the following distributions will be used?

A)the t distribution with 32 degrees of freedom
B)the t distribution with 17 degrees of freedom
C)the t distribution with 13 degrees of freedom
D)the t distribution with 30 degrees of freedom

Question 16

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
Calculate the margin of error for the given data assuming 95% confidence level: n_x = 200
_x = 0.56 n_y = 230
_y = 0.46

A)0.124
B)0.094
C)0.112
D)0.265

Question 17

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A career counselor is interested in examining the salaries earned by graduate business school students at the end of the first year after graduation.In particular,the counselor is interested in seeing whether there is a difference between men and women graduates' salaries.From a random sample of 20 men,the mean salary is found to be $42,780 with a standard deviation of $5,426.From a sample of 12 women,the mean salary is found to be $40,136 with a standard deviation of $4,383.Assume that the random sample observations are from normally distributed populations,and that the population variances are assumed to be equal.
What is the upper confidence limit of the 95% confidence interval for the difference between the population mean salary for men and women?

A)$6,122.835
B)$6,240.833
C)$6,079.79
D)$6,423.781

Question 18

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Independent samples of math scores from students in the U.S.and Europe were collected from normal populations.A sample of 50 students from the U.S.had an average score of 570 while a sample of 50 European students had an average score of 540.The population standard deviations for the average scores of the US and European students are 102 and 115 respectively.
What is the lower confidence limit of the 95% confidence interval for the difference between the population means?

A)-24.82
B)-12.61
C)-29.21
D)-18.24

Question 19

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
The confidence interval for the difference between two population means that are normally distributed where the population variances are unknown but assumed to be equal rely on:

A)the Satterthwaite's approximation.
B)the pooled sample variance.
C)the estimated sample variance.
D)the average sample variance.

Question 20

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 26.5,s₂ = 3.2
What is the lower confidence limit of the 98% confidence interval for the difference between the population means?

A)20.90
B)25.30
C)24.68
D)23.99

Question 21

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 27.5,and s_d = 3.2
Find the margin of error for a 90% confidence interval for the difference in the means of the two populations.

A)2.75
B)2.29
C)1.24
D)1.86

Question 22

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
n_x = 360,
_x = 0.69,n_y = 350,
_y = 0.76
What is the lower confidence limit of the 98% confidence interval for the difference in population proportions?

A)-0.125
B)0.135
C)-0.147
D)0.147

Question 23

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A dependent random sample from two normally distributed populations gives the following results:
n = 20,
= 27.5,and s_d = 3.2
Find the 95% confidence interval for the difference in the means of the two populations.

A)24.58 < μ_d < 26.89
B)26.26 < μ_d < 28.74
C)25.42 < μ_d < 27.93
D)28.29 < μ_d < 30.25

Question 24

To develop a confidence interval for the difference between the means of two populations which are normally distributed and have equal variances,two independent samples of sizes n₁ and n₂ are randomly selected from the two populations.What is the formula used to determine the number of degrees of freedom for the t distribution?

A)n₁ + n₂
B)n₁ + n₂ - 1
C)n₁ + n₂ - 2
D)n₁ + n₂ + 1

Question 25

In a random sample of 500 California residents,350 indicated that they were home owners.In another random sample of 700 Florida residents,455 indicated that they were home owners.What is the 99% confidence interval for the difference between the proportions?

A)0.05 ± 0.070
B)0.05 ± 0.085
C)0.05 ± 0.053
D)0.05 ± 0.045

Question 26

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In calculating the 95% confidence interval for μ₁ - μ₂ the difference between the means of two normally distributed populations,the summary statistics from two independent samples are:
n_x = 10,
= 50,
= 0.64,n_y = 10,
= 40,and
= 1.86.
What is the upper confidence limit of the 95% confidence interval if the Population variances are unknown and are assumed to be equal?

A)11.050
B)11.072
C)12.056
D)10.980

Question 27

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Independent random sampling from two normally distributed populations gives the following results:
n_x = 55,
= 520,σ_x = 30,n_y = 45,
= 482,and σ_y = 24
Assuming equal population variances,determine the number of degrees of freedom for the following: n₁ = 18, = 28;n₂ = 22,and
= 24

A)40
B)4
C)38
D)10

Question 28

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The means and variances are obtained from two independent samples.Assume that the populations from which the samples were drawn have unequal variances.
Determine the number of degrees of freedom for n₁ = 13, = 4,n₂ = 15,and
= 10.

A)24
B)30
C)18
D)12

Question 29

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A confidence interval for the difference between the means of two normally distributed populations based on the following dependent samples is desired:

What is the width of the interval?

A)4.86
B)2.56
C)3.24
D)6.48

Question 30

If the population distribution of the differences between means of dependent samples is assumed to be normal,then a 100(1- α)% confidence interval for the difference between two means and dependent samples is given by:

A)
± t_n-1,α/2

B)
± t_n-1,α/2

C)
± t_n-1,α/2

D)
± t_n-1,α/2

Question 31

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A confidence interval for the difference between the means of two normally distributed populations based on the following dependent samples is desired:

If the observed sample means are and
Then a 100(1- α)% confidence interval for the difference between two means,independent samples,and known population variances is given by:

A)
-

± z_α/2


B)
-

± z_α/2


C)
-

± z_α/2
NEWLINE

D)
-

± z_α/2

Question 32

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
For calculating a 95% confidence interval for μ₁ - μ₂ the difference between the means of two normally distributed populations,the summary statistics from two independent samples are:
n_x = 60,
= 180,
= 360,n_y = 45,
= 160,and
= 900.
It is assumed that the Population variances are unknown and are equal.
What is the upper confidence limit of the 95% confidence interval?

A)29.505
B)30.172
C)10.006
D)22.797

Question 33

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Independent random sampling from two normally distributed populations gives the following results:
n_x = 55,
= 520,σ_x = 30,n_y = 45,
= 482,and σ_y = 24
Find the 98% confidence interval for the difference in the means of the two populations.

A)1002 ± 12.58
B)38 ± 12.58
C)38 ± 19.86
D)1002 ± 19.86

Question 34

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
For calculating a 95% confidence interval for μ₁ - μ₂ the difference between the means of two normally distributed populations,the summary statistics from two independent samples are:
n_x = 60,
= 180,
= 360,n_y = 45,
= 160,and
= 900.
It is assumed that the Population variances are unknown and are equal.
What is the lower confidence limit of the 95% confidence interval?

A)29.505
B)11.587
C)10.495
D)22.797

Question 35

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In calculating the 95% confidence interval for μ₁ - μ₂ the difference between the means of two normally distributed populations,the summary statistics from two independent samples are:
n_x = 10,
= 50,
= 0.64,n_y = 10,
= 40,and
= 1.86.
What is the lower confidence limit of the 95% confidence interval if the Population variances are unknown and are assumed to be equal?

A)8.880
B)8.950
C)9.020
D)7.650

Question 36

Assuming unknown but equal population variances,determine the number of degrees of freedom for the following: n₁ = 30, = 16.5;n₂ = 45,and
= 17.2.

A)59
B)73
C)61
D)55

Question 37

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Independent random sampling from two normally distributed populations gives the following results:
n_x = 55,
= 520,σ_x = 30,n_y = 45,
= 482,and σ_y = 24
Find the margin of error for a 98% confidence interval for the difference in the means of the two populations.

A)8.50
B)19.86
C)15.77
D)12.58

Question 38

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A confidence interval for the difference between the means of two normally distributed populations based on the following dependent samples is desired:

What is the upper confidence limit of the 95% confidence interval?

A)0.42
B)1.48
C)0.043
D)0.05

Question 39

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A confidence interval for the difference between the means of two normally distributed populations based on the following dependent samples is desired:

What is the lower confidence limit of the 95% confidence interval?

A)-2.82
B)-3.88
C)2.45
D)3.88

Question 40

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A confidence interval for the difference between the means of two normally distributed populations based on the following dependent samples is desired:

What is the margin of error at 95% Confidence interval?

A)2.76
B)1.62
C)1.25
D)2.00

Question 41

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
From a random sample of ten students in an operations management class that uses group-learning techniques,the mean examination score was found to be 82.75 and the sample standard deviation was 3.24.For an independent random sample of eight students in another marketing research class that does not use group-learning techniques,the sample mean and standard deviation of exam scores were 75.62 and 7.27,respectively.It is assumed that the and unknown population variances are not assumed to be equal.
Find the 95% confidence for the difference between the two population mean scores.

A)7.13 ± 13.29
B)7.13 ± 0.97
C)7.13 ± 14.26
D)7.13 ± 6.16

Question 42

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A restaurant manager was in charge of purchasing new microwaves for his restaurant.The choices were narrowed to two available models.Since the two models cost about the same,the manager was interested in determining whether there was a difference in the amount of power consumed when operated at high voltages.Based on two independent random samples,the following summary information was computed:

Find a 99% confidence interval for the difference in the amount of power consumed at high voltages by the two models.

A)0.2 ± 0.86
B)0.2 ± 0.58
C)0.2 ± 0.64
D)0.2 ± 0.77

Question 43

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
n₁ = 35,
₁ = 140
= 60.84;n₂ = 48,
₂ = 130,and
= 156.25
What is the lower confidence limit of the 95% confidence interval?

A)8.233
B)6.333
C)10.233
D)5.233

Question 44

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Two dependent random samples from two normally distributed populations gives the following results:
n = 10;
= 20.5;s_d = 3.2
Find the lower confidence limit of the 95% confidence interval for the difference between the means of the two populations.

A)13.48
B)17.71
C)22.79
D)25.83

Question 45

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The residents of Austin,Texas,complain that parking fines given in their city are higher than the parking fines that are given in Houston.Independent random samples of the amounts paid by residents for parking tickets in each of two cities over the last four months were obtained.Assume the population variances are equal.These amounts were as follows:

What is the sample variance of the parking fines issued in Austin?

A)404.49
B)230.69
C)364.04
D)201.86

Question 46

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
From a random sample of ten students in an operations management class that uses group-learning techniques,the mean examination score was found to be 82.75 and the sample standard deviation was 3.24.For an independent random sample of eight students in another marketing research class that does not use group-learning techniques,the sample mean and standard deviation of exam scores were 75.62 and 7.27,respectively.It is assumed that the and unknown population variances are not assumed to be equal.
Determine the number of degrees of freedom.

A)10
B)15
C)20
D)25

Question 47

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
n₁ = 35,
₁ = 140
= 60.84;n₂ = 48,
₂ = 130,and
= 156.25
What is the upper confidence limit of the 95% confidence interval?

A)16.879
B)12.987
C)15.233
D)14.767

Question 48

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In a random sample of 150 large retailers,110 used regression as a method of forecasting.In an independent random sample of 180 small retailers,90 used regression as a method of forecasting.
Find the 90% confidence interval for the difference between the two population proportions.

A)0.23 ± 0.0482
B)0.23 ± 0.0854
C)1.23 ± 0.0482
D)1.23 ± 0.0854

Question 49

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The residents of Austin,Texas,complain that parking fines given in their city are higher than the parking fines that are given in Houston.Independent random samples of the amounts paid by residents for parking tickets in each of two cities over the last four months were obtained.Assume the population variances are equal.These amounts were as follows:

What is the mean of the parking fines issued in Austin?

A)97.88
B)146.75
C)78.30
D)117.40

Question 50

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The means and variances are obtained from two independent samples.Assume that the populations from which the samples were drawn have unequal variances.
Determine the number of degrees of freedom for n₁ = 9, = 24,n₂ = 14,and
= 36

A)14
B)20
C)25
D)32

Question 51

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A restaurant manager was in charge of purchasing new microwaves for his restaurant.The choices were narrowed to two available models.Since the two models cost about the same,the manager was interested in determining whether there was a difference in the amount of power consumed when operated at high voltages.Based on two independent random samples,the following summary information was computed:

Find a 90% confidence interval for the difference in the amount of power consumed at high voltages by the two models.

A)0.2 ± 0.49
B)0.2 ± 0.16
C)0.2 ± 0.05
D)0.2 ± 1.28

Question 52

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In a random sample of 150 large retailers,110 used regression as a method of forecasting.In an independent random sample of 180 small retailers,90 used regression as a method of forecasting.
Find the margin of error for a 90% confidence interval.

A)0.1453
B)0.0482
C)0.0854
D)0.1792

Question 53

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Two dependent random samples from two normally distributed populations gives the following results:
n = 10;
= 20.5;s_d = 3.2
Find the width of the 95% confidence interval.

A)2.29
B)3.86
C)4.58
D)5.92

Question 54

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The residents of Austin,Texas,complain that parking fines given in their city are higher than the parking fines that are given in Houston.Independent random samples of the amounts paid by residents for parking tickets in each of two cities over the last four months were obtained.Assume the population variances are equal.These amounts were as follows:

Calculate the pooled sample variance.

A)595.042
B)468.006
C)328.455
D)554.593

Question 55

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Two dependent random samples from two normally distributed populations gives the following results:
n = 10;
= 20.5;s_d = 3.2
Find the upper confidence limit of the 95% confidence interval for the difference between the means of the two populations.

A)13.48
B)18.21
C)22.29
D)25.83

Question 56

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
n₁ = 35,
₁ = 140
= 60.84;n₂ = 48,
₂ = 130,and
= 156.25
Find the margin of error for a 95% confidence interval for the difference in the means of the two populations assuming that the population variances are equal.

A)4.002
B)4.767
C)5.365
D)3.645

Question 57

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The residents of Austin,Texas,complain that parking fines given in their city are higher than the parking fines that are given in Houston.Independent random samples of the amounts paid by residents for parking tickets in each of two cities over the last four months were obtained.Assume the population variances are equal.These amounts were as follows:

What is the mean of the parking fines issued in Houston?

A)97.88
B)146.75
C)78.30
D)117.40

Question 58

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The residents of Austin,Texas,complain that parking fines given in their city are higher than the parking fines that are given in Houston.Independent random samples of the amounts paid by residents for parking tickets in each of two cities over the last four months were obtained.Assume the population variances are equal.These amounts were as follows:

What is the sample variance of the parking fines issued in Houston?

A)404.49
B)230.69
C)364.04
D)201.86

Question 59

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A restaurant manager was in charge of purchasing new microwaves for his restaurant.The choices were narrowed to two available models.Since the two models cost about the same,the manager was interested in determining whether there was a difference in the amount of power consumed when operated at high voltages.Based on two independent random samples,the following summary information was computed:

Find a 95% confidence interval for the difference in the amount of power consumed at high voltages by the two models.

A)0.2 ± 0.49
B)0.2 ± 0.58
C)0.2 ± 0.64
D)0.2 ± 1.28

Question 60

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Two dependent random samples from two normally distributed populations gives the following results:
n = 10;
= 20.5;s_d = 3.2
Find the margin of error for a 95% confidence interval for the difference between the means of the two populations.

A)2.29
B)5.86
C)3.44
D)8.10

Question 61

Calculate the pooled sample variance.

A)410.936
B)680.789
C)590.876
D)699.121

Question 62

Determine the number of degrees of freedom.

A)16
B)22
C)19
D)14

Question 63

Find the 95% confidence interval for the difference in the mean costs of parking tickets in these two cities.

A)19.57 ± 20.00
B)19.57 ± 20.38
C)19.57 ± 18.98
D)19.57 ± 17.68

Question 64

The formula used to determine the number of degrees of freedom for the t distribution is (n₁ + n₂ - 2).

Question 65

The margin of error of confidence intervals for the difference between two means,independent samples,and known population variances is given by
-
± z_α/2


.

Question 66

A 100(1- α)% confidence interval for the difference between two means,independent samples,and known population variances is given by
-
± z_α/2
.

Question 67

In order to measure the effectiveness of a weight loss program,members are weighed at the beginning and the end of the program.This is an example of independent samples with unequal population variances.

Question 68

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Consider the data in the table below.

What is the sample variance of the Group 1?

A)345.98
B)234.56
C)366.01
D)255.89

Question 69

Certain situations that involve dependent samples are known as repeated measurements.

Question 70

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The residents of Austin,Texas,complain that parking fines given in their city are higher than the parking fines that are given in Houston.Independent random samples of the amounts paid by residents for parking tickets in each of two cities over the last four months were obtained.Assume the population variances are equal.These amounts were as follows:

Determine the number of degrees of freedom.

A)18
B)16
C)20
D)9

Question 71

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Consider the data in the table below.

What is the mean of the Group 2?

A)97.88
B)100.13
C)78.30
D)119.70

Question 72

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The residents of Austin,Texas,complain that parking fines given in their city are higher than the parking fines that are given in Houston.Independent random samples of the amounts paid by residents for parking tickets in each of two cities over the last four months were obtained.Assume the population variances are equal.These amounts were as follows:

Find the 98% confidence interval for the difference in the mean costs of parking tickets in these two cities.

A)19.52 ± 25.37
B)19.52 ± 20.38
C)19.52 ± 22.77
D)19.52 ± 22.21

Question 73

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Consider the data in the table below.

What is the sample variance of the Group 2?

A)468.70
B)366.01
C)456.19
D)490.67

Question 74

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Consider the data in the table below.

What is the mean of the Group 1?

A)119.70
B)121.67
C)115.60
D)117.65

Question 75

While constructing a confidence interval for the mean difference in paired data,as the sample size increases,the width of the interval also increases.

Question 76

The mean of the sampling distribution of the difference between sample proportions,
₁ -
₂,is equal to the difference between the corresponding population proportions,P₁ - P₂.

Question 77

Assuming equal population variances,determine the number of degrees of freedom for the following: n₁ = 16,
= 25;n₂ = 20,and
= 30

A)36
B)18
C)38
D)34

Question 78

The Student's t-distribution is required to determine the confidence interval for the difference between two normal population means with unknown population variances.

Question 79

The estimation procedure used to compare two population means when the sample values from the first population are influenced by the sample values from the second population is known as matched pairs.

Question 80

For confidence intervals of two means that are dependent samples,the margin of error is equal to
t_n-1,tα/s


.