Question 1

In hypothesis tests about p1 - p2, the pooled estimator of p is a(n)

Accepted Answer

A)   simple average of $\bar { p } _ { 1 }$ and  $\bar { p } _ { 2 }$ . 
B)  weighted average of $\bar { p } _ { 1 }$ and $\bar { p } _ { 2 }$ . 
C)   geometric average of $\bar { p } _ { 1 }$ and $\bar { p } _ { 2 }$ . 
D)   exponential average of $\bar { p } _ { 1 }$ and $\bar { p } _ { 2 }$ . 
A)   simple average of $\bar { p } _ { 1 }$ and  $\bar { p } _ { 2 }$ . 
B)  weighted average of $\bar { p } _ { 1 }$ and $\bar { p } _ { 2 }$ . 
C)   geometric average of $\bar { p } _ { 1 }$ and $\bar { p } _ { 2 }$ . 
D)   exponential average of $\bar { p } _ { 1 }$ and $\bar { p } _ { 2 }$ . B

Question 2

Two major automobile manufacturers have produced compact cars with engines of the same size.We are interested in determining whether or not there is a significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles.A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance.The following data (in miles per gallon) show the results of the test.Assume the population of differences is normally distributed. $\begin{array}{lll}
\text { Driver} & \text {  Manufacturer A } & \text { Manufacturer B } \
1 & 32 & 28 \
2 & 27 & 22 \
3 & 26 & 27 \
4 & 26 & 24 \
5 & 25 & 24 \
6 & 29 & 25 \
7 & 31 & 28 \
8 & 25 & 27
\end{array}$ 
 The mean of the differences is

Accepted Answer

A)  .5. 
B)  1.5. 
C)  2.0. 
D)  2.5. 
A)  .5. 
B)  1.5. 
C)  2.0. 
D)  2.5. C

Question 3

The sampling distribution of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is approximated by a normal distribution if _____ are all greater than or equal to 5.

Accepted Answer

A)   n1p2, p2(1 - n2), n2p1, p1(1 - n1) 
B)   n1p1, p1(1 - n1), n2p2, p2(1 - n2) 
C)   n1p2, n1(1 - p2), n2p1, n2(1 - p1) 
D)   n1p1, n1(1 - p1), n2p2, n2(1 - p2) 
A)   n1p2, p2(1 - n2), n2p1, p1(1 - n1) 
B)   n1p1, p1(1 - n1), n2p2, p2(1 - n2) 
C)   n1p2, n1(1 - p2), n2p1, n2(1 - p1) 
D)   n1p1, n1(1 - p1), n2p2, n2(1 - p2) D

Question 4

The results of a recent poll on the preference of teenagers regarding the types of music they listen to are shown below. $\begin{array}{lll}
\text { Music Type } & \text { Teenagers Surveyed } & \text { Teenagers Favoring } \
&&\text { Phis Typ e } \
\text { Pop } & 800 & 384 \
\text { Rap } & 900 & 450
\end{array}$   The 95% confidence interval for the difference between the two population proportions is

Accepted Answer

A)  .5 to .52. 
B)  .48 to .5. 
C)  .028 to .068. 
D)  -.068 to .028. 
A)  .5 to .52. 
B)  .48 to .5. 
C)  .028 to .068. 
D)  -.068 to .028.

Question 5

When developing an interval estimate for the difference between two population means with sample sizes of n1 and n2,

Accepted Answer

A)  n1 must be equal to n2. 
B)  n1 must be smaller than n2. 
C)  n1 must be larger than n2. 
D)  n1 and n2 can be of different sizes. 
A)  n1 must be equal to n2. 
B)  n1 must be smaller than n2. 
C)  n1 must be larger than n2. 
D)  n1 and n2 can be of different sizes.

Question 6

If two independent large samples are taken from two populations, the sampling distribution of the difference between the two sample means

Accepted Answer

A)  can be approximated by any distribution. 
B)  will have a variance of one. 
C)  can be approximated by a normal distribution. 
D)  will have a mean of one. 
A)  can be approximated by any distribution. 
B)  will have a variance of one. 
C)  can be approximated by a normal distribution. 
D)  will have a mean of one.

Question 7

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed. $\begin{array}{lll}
\text { Individual } & \text { Method 1 } & \text { Method 2 } \
1 & 7 & 5 \
2 & 5 & 9 \
3 & 6 & 8 \
4 & 7 & 7 \
5 & 5 & 6
\end{array}$ 
 The point estimate for the difference between the means of the two populations (Method 1 - Method 2) is

Accepted Answer

A)  -1. 
B)  0. 
C)  -4. 
D)  2. 
A)  -1. 
B)  0. 
C)  -4. 
D)  2.

Question 8

In order to determine whether or not there is a significant difference between the mean hourly wages paid by two companies (of the same industry), the following data have been accumulated. $$\begin{array} { l l l } 
 & \text { Company A } & \text { Company B } \
\text { Sample size } & 80 & 60 \
\text { Sample mean } & \$ 16.75 & \$ 16.25 \
\text { Population standard deviation } &\$ 1.00 & \$ .95
\end{array}$$   A point estimate for the difference between the two population means is

Accepted Answer

A)  20. 
B)  .50. 
C)  .25. 
D)  1.00. 
A)  20. 
B)  .50. 
C)  .25. 
D)  1.00.

Question 9

In order to determine whether or not there is a significant difference between the mean hourly wages paid by two companies (of the same industry), the following data have been accumulated. $$\begin{array} { l l l } 
 & \text { Company A } & \text { Company B } \
\text { Sample size } & 80 & 60 \
\text { Sample mean } & \$ 16.75 & \$ 16.25 \
\text { Population standard deviation } &\$ 1.00 & \$ .95
\end{array}$$   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. 
A)  should be rejected. 
B)  should not be rejected. 
C)  should be revised. 
D)  should not be tested.

Question 10

The management of a department store is interested in estimating the difference between the mean credit purchases of customers using the store's credit card versus those customers using a national major credit card.You are given the following information. $$\begin{array} { l l l } 
& \text { Store's Card } & \text { Major Credit Card } \
\text { Sample size } & 64 & 49 \
\text { Sample mean } & \$ 140 & \$ 125 \
\text { Population standard deviation } & \$ 10 & \$ 8
\end{array}$$   A 95% confidence interval estimate for the difference between the average purchases of all customers using the two different credit cards is

Accepted Answer

A)  13.31 to 16.69. 
B)  11.68 to 18.32. 
C)  12.22 to 17.78. 
D)  13.04 to 16.96. 
A)  13.31 to 16.69. 
B)  11.68 to 18.32. 
C)  12.22 to 17.78. 
D)  13.04 to 16.96.

Question 11

The following information was obtained from independent random samples taken of two populations. Assume normally distributed populations with equal variances. $$\begin{array} { l l l } 
& \text { Sample 1 } & \text { Sample 2 } \
\text { Sample Mean } & 45 & 42 \
\text { Sample Variance } & 85 & 90 \
\text { Sample Size } & 10 & 12
\end{array}$$

The point estimate for the difference between the means of the two populations is

Accepted Answer

A)  0. 
B)  2. 
C)  3. 
D)  15. 
A)  0. 
B)  2. 
C)  3. 
D)  15.

Question 12

The standard error of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ is the

Accepted Answer

A)  pooled estimator of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ . 
B)  variance of the sampling distribution of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ . 
C)  standard deviation of the sampling distribution of $$\bar { x } _ { 1 }$$ - $\bar { x } _ { 2 }$ . 
D)  margin of error of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ . 
A)  pooled estimator of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ . 
B)  variance of the sampling distribution of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ . 
C)  standard deviation of the sampling distribution of $$\bar { x } _ { 1 }$$ - $\bar { x } _ { 2 }$ . 
D)  margin of error of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ .

Question 13

A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago.A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken.You are given the following information. $\begin{array}{ll}
&\text { Today } & \text { Five Years Ago } \
\bar {x}&82 & 88 \
\sigma^2&112.5 & 54 \
n&45 & 36
\end{array}$ 
 What is the conclusion that can be reached about the difference in the average final examination scores between the two classes? (Use a .05 level of significance.)

Accepted Answer

A)  There is a statistically significant difference in the average final examination scores between the two classes. 
B)  There is no statistically significant difference in the average final examination scores between the two classes. 
C)  It is impossible to make a decision on the basis of the information given. 
D)  The students who enrolled in statistics today are the same students who enrolled five years ago. 
A)  There is a statistically significant difference in the average final examination scores between the two classes. 
B)  There is no statistically significant difference in the average final examination scores between the two classes. 
C)  It is impossible to make a decision on the basis of the information given. 
D)  The students who enrolled in statistics today are the same students who enrolled five years ago.

Question 14

In order to determine whether or not there is a significant difference between the mean hourly wages paid by two companies (of the same industry), the following data have been accumulated. $$\begin{array} { l l l } 
 & \text { Company A } & \text { Company B } \
\text { Sample size } & 80 & 60 \
\text { Sample mean } & \$ 16.75 & \$ 16.25 \
\text { Population standard deviation } &\$ 1.00 & \$ .95
\end{array}$$   The p-value is

Accepted Answer

A)  .0013. 
B)  .0026. 
C)  .0042. 
D)  .0084. 
A)  .0013. 
B)  .0026. 
C)  .0042. 
D)  .0084.

Question 15

When each data value in one sample is matched with a corresponding data value in another sample, the samples are known as

Accepted Answer

A)  corresponding samples. 
B)  matched samples. 
C)  independent samples. 
D)  pooled samples. 
A)  corresponding samples. 
B)  matched samples. 
C)  independent samples. 
D)  pooled samples.

Question 16

The results of a recent poll on the preference of shoppers regarding two products are shown below. $$\begin{array} { l l l } 
\text { Product } & \text { Shoppers Surveyed } & \text { Shoppers Favoring } \
& & \text { This Product } \
\text { A } & 800 & 560 \
\text { B } &900 & 612
\end{array}$$
 The standard error of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is

Accepted Answer

A)  .025. 
B)  .044. 
C)  .0225. 
D)  .68. 
A)  .025. 
B)  .044. 
C)  .0225. 
D)  .68.

Question 17

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed. $\begin{array}{lll}
\text { Individual } & \text { Method 1 } & \text { Method 2 } \
1 & 7 & 5 \
2 & 5 & 9 \
3 & 6 & 8 \
4 & 7 & 7 \
5 & 5 & 6
\end{array}$ 
The 95% confidence interval for the difference between the two population means is

Accepted Answer

A)  -3.776 to 1.776. 
B)  -2.776 to 2.776. 
C)  -1.776 to 2.776. 
D)  -1.776 to 1.776. 
A)  -3.776 to 1.776. 
B)  -2.776 to 2.776. 
C)  -1.776 to 2.776. 
D)  -1.776 to 1.776.

Question 18

In order to determine whether or not there is a significant difference between the mean hourly wages paid by two companies (of the same industry), the following data have been accumulated. $$\begin{array} { l l l } 
 & \text { Company A } & \text { Company B } \
\text { Sample size } & 80 & 60 \
\text { Sample mean } & \$ 16.75 & \$ 16.25 \
\text { Population standard deviation } &\$ 1.00 & \$ .95
\end{array}$$   The test statistic is

Accepted Answer

A)  .098. 
B)  1.645. 
C)  2.75. 
D)  3.01. 
A)  .098. 
B)  1.645. 
C)  2.75. 
D)  3.01.

Question 19

In order to estimate the difference between the average hourly wages of employees of two branches of a department store, the following data have been gathered. $\begin{array}{lll}
& \text { Downtown Store } & \text { North Mall Store } \
 \text { Sample size } & 25 & 20 \
\text { Sample mean }& \$ 9 & \$ 8 \
\text { Sample standard deviation } & \$ 2 & \$ 1
\end{array}$   A point estimate for the difference between the two population means is

Accepted Answer

A)  1. 
B)  2. 
C)  3. 
D)  4. 
A)  1. 
B)  2. 
C)  3. 
D)  4.

Question 20

Two major automobile manufacturers have produced compact cars with engines of the same size.We are interested in determining whether or not there is a significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles.A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance.The following data (in miles per gallon) show the results of the test.Assume the population of differences is normally distributed. $\begin{array}{lll}
\text { Driver} & \text {  Manufacturer A } & \text { Manufacturer B } \
1 & 32 & 28 \
2 & 27 & 22 \
3 & 26 & 27 \
4 & 26 & 24 \
5 & 25 & 24 \
6 & 29 & 25 \
7 & 31 & 28 \
8 & 25 & 27
\end{array}$ 
At $\alpha$ = .10, the null hypothesis

Accepted Answer

A)  should not be rejected. 
B)  should be rejected. 
C)  should be revised. 
D)  should not be tested. 
A)  should not be rejected. 
B)  should be rejected. 
C)  should be revised. 
D)  should not be tested.

In hypothesis tests about p₁ - p₂, the pooled estimator of p is a(n)

The sampling distribution of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is approximated by a normal distribution if _____ are all greater than or equal to 5.

The results of a recent poll on the preference of teenagers regarding the types of music they listen to are shown below. Music Type Teenagers Surveyed Teenagers Favoring Phis Typ e Pop 800 384 Rap 900 450 The 95% confidence interval for the difference between the two population proportions is

When developing an interval estimate for the difference between two population means with sample sizes of n₁ and n₂,

If two independent large samples are taken from two populations, the sampling distribution of the difference between the two sample means

The standard error of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ is the

When each data value in one sample is matched with a corresponding data value in another sample, the samples are known as

The results of a recent poll on the preference of shoppers regarding two products are shown below. Product Shoppers Surveyed Shoppers Favoring This Product A 800 560 B 900 612 The standard error of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed. Individual Method 1 Method 2 1 7 5 2 5 9 3 6 8 4 7 7 5 5 6 The 95% confidence interval for the difference between the two population means is

Data and Statistics

Descriptive Statistics: Tabulargraphical

Descriptive Statistics: Numerical

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Inferences About Population Variances

Comparing Multiple Proportions, Test of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Filters

Exam 10: Inference About Means and Proportions With Two Populations

In hypothesis tests about p1 - p2, the pooled estimator of p is a(n)

The sampling distribution of pˉ1\bar { p } _ { 1 }pˉ​1​ - pˉ2\bar { p } _ { 2 }pˉ​2​ is approximated by a normal distribution if _____ are all greater than or equal to 5.

The results of a recent poll on the preference of teenagers regarding the types of music they listen to are shown below. Music Type Teenagers Surveyed Teenagers Favoring Phis Typ e Pop 800 384 Rap 900 450 The 95% confidence interval for the difference between the two population proportions is

When developing an interval estimate for the difference between two population means with sample sizes of n1 and n2,

If two independent large samples are taken from two populations, the sampling distribution of the difference between the two sample means

The standard error of xˉ1\bar { x } _ { 1 }xˉ1​ - xˉ2\bar { x } _ { 2 }xˉ2​ is the

When each data value in one sample is matched with a corresponding data value in another sample, the samples are known as

The results of a recent poll on the preference of shoppers regarding two products are shown below. Product Shoppers Surveyed Shoppers Favoring This Product A 800 560 B 900 612 The standard error of pˉ1\bar { p } _ { 1 }pˉ​1​ - pˉ2\bar { p } _ { 2 }pˉ​2​ is

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed. Individual Method 1 Method 2 1 7 5 2 5 9 3 6 8 4 7 7 5 5 6 The 95% confidence interval for the difference between the two population means is

Data and Statistics

Descriptive Statistics: Tabulargraphical

Descriptive Statistics: Numerical

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Inferences About Population Variances

Comparing Multiple Proportions, Test of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Filters

In hypothesis tests about p₁ - p₂, the pooled estimator of p is a(n)

The sampling distribution of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is approximated by a normal distribution if _____ are all greater than or equal to 5.

When developing an interval estimate for the difference between two population means with sample sizes of n₁ and n₂,

The standard error of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ is the

The results of a recent poll on the preference of shoppers regarding two products are shown below. Product Shoppers Surveyed Shoppers Favoring This Product A 800 560 B 900 612 The standard error of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is