Question 1

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 2

In order to estimate the difference between the average yearly salaries of top managers in private and governmental organizations, the following information was gathered.   ​
Develop an interval estimate for the difference between the average yearly salaries of top managers of the two sectors.Use 95% confidence and give your answers in dollars.

Accepted Answer

The answer of In order to estimate the difference between...

Question 3

Salary information regarding male and female employees of a large company is shown below.   ​ The standard error of the difference between the two sample means is

Accepted Answer

A)  4. 
B)  7.46. 
C)  4.24. 
D)  2.0. 
A)  4. 
B)  7.46. 
C)  4.24. 
D)  2.0.

Question 4

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.   ​ 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 5

A poll was taken this year asking college students if they considered themselves overweight.A similar poll was taken five years ago.Results are summarized below.Has the proportion increased significantly? Let α = .05.

Accepted Answer

H₀: p₁ - p₂ ≤ 0 H_a: p₁ - p₂ > 0 z =

Question 6

In testing the null hypothesis H0:  1 - ?2 = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

Accepted Answer

A)  ?.0485. 
B)  ?.0970. 
C)  ?.9515. 
D)  ?.9030. 
A)  ?.0485. 
B)  ?.0970. 
C)  ?.9515. 
D)  ?.9030.

Question 7

Of the two production methods, a company wants to identify the method with the smaller population mean completion time.One sample of workers is selected and each worker first uses one method and then uses the other method.The sampling procedure being used to collect completion time data is based on​

Accepted Answer

A)  ​worker samples. 
B)  ​pooled samples. 
C)  ​independent samples. 
D)  ​matched samples. 
A)  ​worker samples. 
B)  ​pooled samples. 
C)  ​independent samples. 
D)  ​matched samples.

Question 8

To compute an interval estimate for the difference between the means of two populations, the t distribution

Accepted Answer

A)  is restricted to small sample situations. 
B)  is not restricted to small sample situations. 
C)  can be applied when the populations have equal means. 
D)  can be applied only when the populations have equal standard deviations. 
A)  is restricted to small sample situations. 
B)  is not restricted to small sample situations. 
C)  can be applied when the populations have equal means. 
D)  can be applied only when the populations have equal standard deviations.

Question 9

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed.   ​ 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 10

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.   ​ 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 11

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.   ​ 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.

Question 12

The results of a recent poll on the preference of shoppers regarding two products are shown below.   ​ The standard error of   -   is

Accepted Answer

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

Question 13

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.   ​ The p-value is

Accepted Answer

A)  .0010. 
B)  .0021. 
C)  .0042. 
D)  .9990. 
A)  .0010. 
B)  .0021. 
C)  .0042. 
D)  .9990.

Question 14

The standard error of   -   is the

Accepted Answer

A)  pooled estimator of   -   . 
B)  variance of the sampling distribution of   -   . 
C)  standard deviation of the sampling distribution of   -   . 
D)  margin of error of   -   .​ 
A)  pooled estimator of   -   . 
B)  variance of the sampling distribution of   -   . 
C)  standard deviation of the sampling distribution of   -   . 
D)  margin of error of   -   .​

Question 15

The business manager of a local health clinic is interested in estimating the difference between the fees for extended office visits in her center and the fees of a newly opened group practice.She gathered the following information regarding the two offices.   ​
Develop a 95% confidence interval estimate for the difference between the average fees of the two offices.

Accepted Answer

The answer of The business manager of a local health...

Question 16

Independent random samples of managers' yearly salaries (in $1000) taken from governmental and private organizations provided the following information.At a .05 level of significance, test to determine if there is a significant difference between the average salaries of the managers in the two sectors.

Accepted Answer

H₀: μ₁ - μ₂ = 0 H_a: μ₁ - μ₂ ≠ 0 df = 56; tes

Question 17

The following data present the number of computer units sold per day by a sample of 6 salespersons before and after a bonus plan was implemented.   ​
Using a .05 level of significance, test to see if the bonus plan was effective.That is, did the bonus plan actually increase sales? ​Assume the population of differences is normally distributed.Let d = After - Before.

Accepted Answer

H₀: μd ≤ 0 H_a: μd > 0 t = 0; p

Question 18

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.   ​ A 95% interval estimate for the difference between the two population means is

Accepted Answer

A)  .071 to 1.929. 
B)  .226 to 1.774. 
C)  1.09 to 4.078. 
D)  1.078 to 2.922. 
A)  .071 to 1.929. 
B)  .226 to 1.774. 
C)  1.09 to 4.078. 
D)  1.078 to 2.922.

Question 19

Regarding inferences about the difference between two population means, the sampling design that uses a pooled sample variance in cases of equal population standard deviations is based on

Accepted Answer

A)  ​research samples. 
B)  ​pooled samples. 
C)  ​independent samples. 
D)  conditional samples. 
A)  ​research samples. 
B)  ​pooled samples. 
C)  ​independent samples. 
D)  conditional samples.

Question 20

A potential investor conducted a 49-day survey in each of the North Mall and South Mall theaters in order to determine the difference between the average daily attendance at these two theaters.The North Mall theater averaged 720 patrons per day with a variance of 100; while the South Mall theater averaged 700 patrons per day with a variance of 96.Develop an interval estimate for the difference between the average daily attendance at the two theaters.Use a confidence coefficient of .95.

Accepted Answer

16.03 to 2

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

Salary information regarding male and female employees of a large company is shown below. The standard error of the difference between the two sample means is

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. A point estimate for the difference between the two population means is

A poll was taken this year asking college students if they considered themselves overweight.A similar poll was taken five years ago.Results are summarized below.Has the proportion increased significantly? Let α = .05.

In testing the null hypothesis H₀: ₁ - ?₂ = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

Of the two production methods, a company wants to identify the method with the smaller population mean completion time.One sample of workers is selected and each worker first uses one method and then uses the other method.The sampling procedure being used to collect completion time data is based on

To compute an interval estimate for the difference between the means of two populations, the t distribution

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed. The point estimate for the difference between the means of the two populations (Method 1 - Method 2) is

The results of a recent poll on the preference of shoppers regarding two products are shown below. The standard error of - is

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. The p-value is

The standard error of - is the

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. A 95% interval estimate for the difference between the two population means is

Regarding inferences about the difference between two population means, the sampling design that uses a pooled sample variance in cases of equal population standard deviations is based on

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Inferences About Population Variances

Comparing Multiple Proportions, Tests of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

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Exam 10: Inference About Means and Proportions With Two Populations

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

Salary information regarding male and female employees of a large company is shown below. ​ The standard error of the difference between the two sample means is

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. ​ A point estimate for the difference between the two population means is

A poll was taken this year asking college students if they considered themselves overweight.A similar poll was taken five years ago.Results are summarized below.Has the proportion increased significantly? Let α = .05.

In testing the null hypothesis H0: 1 - ?2 = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

To compute an interval estimate for the difference between the means of two populations, the t distribution

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed. ​ The point estimate for the difference between the means of the two populations (Method 1 - Method 2) is

The results of a recent poll on the preference of shoppers regarding two products are shown below. ​ The standard error of - is

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. ​ The p-value is

The standard error of - is the

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. ​ A 95% interval estimate for the difference between the two population means is

Regarding inferences about the difference between two population means, the sampling design that uses a pooled sample variance in cases of equal population standard deviations is based on

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Inferences About Population Variances

Comparing Multiple Proportions, Tests of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Filters

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

Salary information regarding male and female employees of a large company is shown below. The standard error of the difference between the two sample means is

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. A point estimate for the difference between the two population means is

In testing the null hypothesis H₀: ₁ - ?₂ = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed. The point estimate for the difference between the means of the two populations (Method 1 - Method 2) is

The results of a recent poll on the preference of shoppers regarding two products are shown below. The standard error of - is

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. The p-value is

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. A 95% interval estimate for the difference between the two population means is