Question 1

In testing for the differences between the means of 2 independent populations where the variances in each population are unknown but assumed equal, the degrees of freedom are

Accepted Answer

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

Question 2

SCENARIO 10-3
As part of an evaluation program, a sporting goods retailer wanted to compare the downhill coasting speeds of 4 brands of bicycles.She took 3 of each brand and determined their maximum downhill speeds.The results are presented in miles per hour in the table below. $\begin{array}{lllll}
\text { Trial}&\text { Barth}&\text { Tornado }&\text {Reiser}&\text { Shaw }\
1 & 43 & 37 & 41 & 43 \
2 & 46 & 38 & 45 & 45 \
3 & 43 & 39 & 42 & 46
\end{array}$
-Referring to SCENARIO 10-3, based on the Tukey-Kramer procedure with an overall level of significance of 0.05, the retailer would decide that there is no significant difference between any pair of mean speeds.

Accepted Answer

A) True 
 B)False

Question 3

SCENARIO 10-2
A realtor wants to compare the mean sales-to-appraisal ratios of residential properties sold in four neighborhoods (A, B, C, and D).Four properties are randomly selected from each neighborhood and the ratios recorded for each, as shown below. $ \mathrm{A}: 1.2,1.1,0.9,0.4 $$ \quad C:  1.0,1.5,1.1,1.3 $
B: $ 2.5,2.1,1.9,1.6 $$\quad \mathrm{D}:  0.8,1.3,1.1,0.7 $
Interpret the results of the analysis summarized in the following table:
$\begin{array}{lcclcc}
\hline \text { Source } & \text { df } & \text { SS } & \text { MS } & \text { F } & \text { PR }>\text { F } \
\hline \text { Neighborhoods } & & 3.1819 & 1.0606 & 10.76 & 0.001 \
\text { Error } & 12 & & & & \
\text { Total } & & 4.3644 & & &
\end{array}$
-Referring to SCENARIO 10-2,

Accepted Answer

A) at the 0.05 level of significance, the mean ratios for the 4 neighborhoods are not all the same. 
B) at the 0.01 level of significance, the mean ratios for the 4 neighborhoods are all the same. 
C) at the 0.10 level of significance, the mean ratios for the 4 neighborhoods are not significantly different. 
D) at the 0.05 level of significance, the mean ratios for the 4 neighborhoods are not significantly different from 0. 
A) at the 0.05 level of significance, the mean ratios for the 4 neighborhoods are not all the same. 
B) at the 0.01 level of significance, the mean ratios for the 4 neighborhoods are all the same. 
C) at the 0.10 level of significance, the mean ratios for the 4 neighborhoods are not significantly different. 
D) at the 0.05 level of significance, the mean ratios for the 4 neighborhoods are not significantly different from 0.

Question 4

SCENARIO 10-2
A researcher randomly sampled 30 graduates of an MBA program and recorded data concerning their starting salaries.Of primary interest to the researcher was the effect of gender on starting salaries.
The result of the pooled-variance t-test of the mean salaries of the females (Population 1) and males
(Population 2) in the sample is given below. $\begin{array}{|l|r|}
\hline \text { Hypothesized Difference } & 0 \
\hline \text { Level of Significance } & 0.05 \
\hline\text { Population 1 Sample }\
\hline \text { Sample Size } & 18 \
\hline \text { Sample Mean } & 99210 \
\hline \text { Sample Standard Deviation } & 13577 \
\text { Population 2 Sample } \
\hline \text { Sample Size } & 12 \
\hline \text { Sample Mean } & 105820 \
\hline \text { Sample Standard Deviation } & 11741 \\hline\\hline \text { Difference in Sample Means } & -6610 \
\hline t \text { Test Statistic } & -1.37631 \\hline\\hline {\text { Lower-Tail Test }} \
\hline \text { Lower Critical Value } & -1.70113 \
\hline \text { p-Value } & 0.089816 \
\hline
\end{array}$
-Referring to Scenario 10-2, what is the 99% confidence interval estimate for the difference between two means?

Accepted Answer

-$ 19,881.

Question 5

SCENARIO 10-10
A corporation randomly selects 150 salespeople and finds that 66% who have never taken a self- improvement course would like such a course.The firm did a similar study 10 years ago in which
60% of a random sample of 160 salespeople wanted a self-improvement course.The groups are
assumed to be independent random samples.Let  $\pi$1 and  $\pi$2
represent the true proportion of workers
who would like to attend a self-improvement course in the recent study and the past study, respectively.
-Referring to Scenario 10-10, construct a 99% confidence interval estimate of the difference in proportion of workers who would like to attend a self-improvement course in the recent study and the past study.

Accepted Answer

The answer of SCENARIO 10-10
A corporation randomly selects 150 salespeople...

Question 6

SCENARIO 10-5
To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course.The results are given below. $$\begin{array} { l c c } 
\text { Student } & \begin{array} { c } 
\text { Exam Score } \
\text { BeforeCourse(1) }
\end{array} & \begin{array} { c } 
\text { Exam Score } \
\text { AfterCourse(2) }
\end{array} \
\hline 1 & 530 & 670 \
2 & 690 & 770 \
3 & 910 & 1,000 \
4 & 700 & 710 \
5 & 450 & 550 \
6 & 820 & 870 \
7 & 820 & 770 \
8 & 630 & 610
\end{array}$$
-Referring to Scenario 10-5, the number of degrees of freedom is

Accepted Answer

A) 14. 
B) 13. 
C) 8. 
D) 7. 
A) 14. 
B) 13. 
C) 8. 
D) 7.

Question 7

In a one-factor ANOVA analysis, the among sum of squares and within sum of squares must add up to the total sum of squares.

Accepted Answer

A) True 
 B)False

Question 8

SCENARIO 10-11
The dean of a college is interested in the proportion of graduates from his college who have a job offer on graduation day.He is particularly interested in seeing if there is a difference in this proportion for accounting and economics majors.In a random sample of 100 of each type of major at graduation, he found that 65 accounting majors and 52 economics majors had job offers.If the accounting majors are designated as "Group 1" and the economics majors are designated as "Group
2," perform the appropriate hypothesis test using a level of significance of 0.05.
-Referring to Scenario 10-12, the hypotheses the dean should use are:

Accepted Answer

A) $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } = 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } \neq 0$ B) $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } \neq 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } = 0$ C) $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } \leq 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } > 0$ D) $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } \geq 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } < 0$ A) $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } = 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } \neq 0$ B) $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } \neq 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } = 0$ C) $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } \leq 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } > 0$ D) $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } \geq 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } < 0$

Question 9

SCENARIO 10-10
A corporation randomly selects 150 salespeople and finds that 66% who have never taken a self- improvement course would like such a course.The firm did a similar study 10 years ago in which
60% of a random sample of 160 salespeople wanted a self-improvement course.The groups are
assumed to be independent random samples.Let  $\pi$1 and  $\pi$2
represent the true proportion of workers
who would like to attend a self-improvement course in the recent study and the past study, respectively.
-Referring to Scenario 10-10, what is the estimated standard error of the difference between the two sample proportions?

Accepted Answer

A) 0.629 
B) 0.500 
C) 0.055 
D) 0 
A) 0.629 
B) 0.500 
C) 0.055 
D) 0

Question 10

SCENARIO 10-15
The table below presents the summary statistics for the starting annual salaries (in thousands of dollars) for individuals entering the public accounting and financial planning professions.
 Sample I (public accounting): $\bar { X } _ { 1 } = 60.35 , S _ { 1 } = 3.25 , n _ { 1 } = 12$
Sample II (financial planning): $\bar { X } _ { 2 } = 58.20 , S _ { 2 } = 2.48 , n _ { 2 } = 14$ Test whether the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning assuming that the two population variances are the same.
-Referring to Scenario 10-15, what is the highest level of significance at which a test on a difference in the variances will not be rejected?

Accepted Answer

0.3514 (using Excel or "greate

Question 11

SCENARIO 10-15
The table below presents the summary statistics for the starting annual salaries (in thousands of dollars) for individuals entering the public accounting and financial planning professions.
 Sample I (public accounting): $\bar { X } _ { 1 } = 60.35 , S _ { 1 } = 3.25 , n _ { 1 } = 12$
Sample II (financial planning): $\bar { X } _ { 2 } = 58.20 , S _ { 2 } = 2.48 , n _ { 2 } = 14$ Test whether the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning assuming that the two population variances are the same.
-Referring to Scenario 10-15, what assumptions are necessary for testing whether there is evidence of a difference in the variances to be valid?

Accepted Answer

A) Both sampled populations are normally distributed. 
B) Both samples are random and independent. 
C) Neither (a)nor (b)is necessary. 
D) Both (a)and (b)are necessary. 
A) Both sampled populations are normally distributed. 
B) Both samples are random and independent. 
C) Neither (a)nor (b)is necessary. 
D) Both (a)and (b)are necessary.

Question 12

When testing for differences between the means of 2 related populations, you can use either a one-tail or two-tail test.

Accepted Answer

A) True 
 B)False

Question 13

SCENARIO 10-13
The amount of time required to reach a customer service representative has a huge impact on customer satisfaction.Below is the Excel output from a study to see whether there is evidence of a difference in the mean amounts of time required to reach a customer service representative between two hotels.Assume that the population variances in the amount of time for the two hotels are not equal. $$\begin{array}{l}
\text { t-Test: Two-Sample Assuming Unequal Variances }\
\begin{array} { l r r } 
\hline & \text { Hotel 1 } & \text { Hotel 2 } \
\hline \text { Mean } & 2.214 & 2.0115 \
\text { Variance } & 2.951657 & 3.57855 \
\text { Observations } & 20 & 20 \
\text { Hypothesized Mean Difference } & 0 & \
\text { df } & 38 & \
\text { t Stat } & 0.354386 & \
\text { P } ( T < = t ) \text { one-tail } & 0.362504 & \
\text { t Critical one-tail } & 1.685953 & \
\text { P } ( \text { T } < \text { t) two-tail } & 0.725009 & \
\text { t Critical two-tail } & 2.024394 & \
\hline
\end{array}
\end{array}$$
-Referring to Scenario 10-13, what is(are) the critical value(s) of the relevant hypothesis test if the level of significance is 0.10?

Accepted Answer

A) 1.6860 
B) $\pm$ 1.6860 
C) 2.0244 
D) $\pm$ 2.0244 
A) 1.6860 
B) $\pm$ 1.6860 
C) 2.0244 
D) $\pm$ 2.0244

Question 14

SCENARIO 10-7
A buyer for a manufacturing plant suspects that his primary supplier of raw materials is overcharging.In order to determine if his suspicion is correct, he contacts a second supplier and asks for the prices on various identical materials.He wants to compare these prices with those of his primary supplier.The data collected is presented in the table below, with some summary statistics presented (all of
these might not be necessary to answer the questions which follow).The buyer believes that the differences are normally distributed and will use this sample to perform an appropriate test at a level of significance of 0.01. $$\begin{array} { c c c c } 
\text { Material } & \begin{array} { c } 
\text { Primary } \
\text { Supplier }
\end{array} & \begin{array} { c } 
\text { Secondary } \
\text { Supplier }
\end{array} & \text { Difference } \
\hline 1& { \$ 55 } & \$ 45 & \$ 10 \
2 & \$ 48 & \$ 47 & \$ 1 \
3 & \$ 31 & \$ 32 & - \$ 1 \
4 & \$ 83 & \$ 77 & \$ 6 \
5 & \$ 37 & \$ 37 & \$ 0 \
6 & \$ 55 & \$ 54 & \$ 1 \
\hline \text { Sum: } & \$ 309 & \$ 292 & \$ 17 \
\text { Sum of Squares: } &\$ 17,573 & \$ 15,472 & \$ 139
\end{array}$$
-Referring to Scenario 10-7, the test to perform is a

Accepted Answer

A) pooled-variance t test for differences between two means. 
B) separate-variance t test for differences between two means. 
C) Z test for the difference between two proportions. 
D) paired t-test for the mean difference. 
A) pooled-variance t test for differences between two means. 
B) separate-variance t test for differences between two means. 
C) Z test for the difference between two proportions. 
D) paired t-test for the mean difference.

Question 15

SCENARIO 10-8
A few years ago, Pepsi invited consumers to take the "Pepsi Challenge." Consumers were asked to decide which of two sodas, Coke or Pepsi, they preferred in a blind taste test.Pepsi was interested in determining what factors played a role in people's taste preferences.One of the factors studied was the gender of the consumer.Below are the results of analyses comparing the taste preferences of men and women with the proportions depicting preference for Pepsi. $$\begin{array} { l } 
\text { Males: } n = 109 , p _ { M } = 0.422018 \quad \text { Females: } n = 52 , p _ { F } = 0.25 \
p _ { M } - p _ { F } = 0.172018 \quad Z = 2.11825
\end{array}$$
-Referring to Scenario 10-8, suppose Pepsi wanted to test to determine if the males preferred Pepsi more than the females.Using the test statistic given, compute the appropriate p-value for the test.

Accepted Answer

A) 0.0171 
B) 0.0340 
C) 0.2119 
D) 0.4681 
A) 0.0171 
B) 0.0340 
C) 0.2119 
D) 0.4681

Question 16

SCENARIO 10-11
The dean of a college is interested in the proportion of graduates from his college who have a job offer on graduation day.He is particularly interested in seeing if there is a difference in this proportion for accounting and economics majors.In a random sample of 100 of each type of major at graduation, he found that 65 accounting majors and 52 economics majors had job offers.If the accounting majors are designated as "Group 1" and the economics majors are designated as "Group
2," perform the appropriate hypothesis test using a level of significance of 0.05.
-Referring to Scenario 10-11, the p-value of the test is _.

Accepted Answer

The answer of SCENARIO 10-11
The dean of a college is...

Question 17

SCENARIO 10-14
The use of preservatives by food processors has become a controversial issue.Suppose two preservatives are extensively tested and determined safe for use in meats.A processor wants to compare the preservatives for their effects on retarding spoilage.Suppose 15 cuts of fresh meat are treated with preservative I and 15 are treated with preservative II, and the number of hours until spoilage begins is recorded for each of the 30 cuts of meat.The results are summarized in the table below. $\begin{array} { l l } 
 \text {Preservative I }& \text {Preservative II }\
\bar { X } _ { \mathrm { I } } = 106.4 \text { hours } & \bar { X } _ { \mathrm { II } } = 96.54 \text { hours } \ S _ { \mathrm { I } } = 10.3 \text { hours } & S _ { \mathrm { II } } = 13.4 \text { hours } \end{array}$
-Referring to Scenario 10-14, suppose $\alpha$ = 0.05.Which of the following represents the correct conclusion?

Accepted Answer

A) There is no evidence of a difference in the population variances between preservatives I and II. 
B) There is evidence of a difference in the population variances between preservatives I and II. 
C) There is no evidence that the population variances between preservatives I and II are the same. 
D) There is evidence that the population variances between preservatives I and II are the same. 
A) There is no evidence of a difference in the population variances between preservatives I and II. 
B) There is evidence of a difference in the population variances between preservatives I and II. 
C) There is no evidence that the population variances between preservatives I and II are the same. 
D) There is evidence that the population variances between preservatives I and II are the same.

Question 18

SCENARIO 10-1
An airline wants to select a computer software package for its reservation system.Four software packages (1, 2, 3, and 4) are commercially available.The airline will choose the package that bumps as few passengers as possible during a month.An experiment is set up in which each package is used to make reservations for 5 randomly selected weeks.(A total of 20 weeks was included in the experiment.) The number of passengers bumped each week is obtained, which gives rise to the following Excel output: $$\begin{array} { l l l l l l l } 
\text { ANOVA } & & & & & \
\hline \text { Source of Variation } & \text { SS } & \text { df } & \text { MS } & F & \text { P-value } & \text { F crit } \
\hline \text { Between Groups } & 212.4 & 3 & & 8.304985 & 0.001474 & 3.238867 \
\text { Within Groups } & 136.4 & & 8.525 & & & \\
\text { Total } & 348.8 & & & & & \
\hline
\end{array}$$
-Referring to SCENARIO 10-1, the within groups degrees of freedom is

Accepted Answer

A) 3 
B) 4 
C) 16 
D) 19 
A) 3 
B) 4 
C) 16 
D) 19

Question 19

In testing for the differences between the means of two related populations, thehypothesis is the hypothesis of "no differences."

Accepted Answer

The answer of In testing for the differences between the...

Question 20

When testing for the difference between 2 population variances with sample sizes of n1 = 8 andn2 = 10, where n1 has the larger variance, the number of degrees of freedom are

Accepted Answer

A) 8 and 10. 
B) 7 and 9. 
C) 18. 
D) 16. 
A) 8 and 10. 
B) 7 and 9. 
C) 18. 
D) 16.

In testing for the differences between the means of 2 independent populations where the variances in each population are unknown but assumed equal, the degrees of freedom are

In a one-factor ANOVA analysis, the among sum of squares and within sum of squares must add up to the total sum of squares.

When testing for differences between the means of 2 related populations, you can use either a one-tail or two-tail test.

In testing for the differences between the means of two related populations, thehypothesis is the hypothesis of "no differences."

When testing for the difference between 2 population variances with sample sizes of n1 = 8 andn2 = 10, where n1 has the larger variance, the number of degrees of freedom are

Defining and Collecting Data

Organizing and Visualizing Variables

Numerical Descriptive Measures

Basic Probability

Discrete Probability Distributions

The Normal Distribution

Sampling Distributions

Confidence Interval Estimation

Fundamentals of Hypothesis Testing: One-Sample Tests

Chi-Square Tests

Simple Linear Regression

Multiple Regression

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Exam 10: Two-Sample Tests

In testing for the differences between the means of 2 independent populations where the variances in each population are unknown but assumed equal, the degrees of freedom are

In a one-factor ANOVA analysis, the among sum of squares and within sum of squares must add up to the total sum of squares.

When testing for differences between the means of 2 related populations, you can use either a one-tail or two-tail test.

In testing for the differences between the means of two related populations, thehypothesis is the hypothesis of "no differences."

When testing for the difference between 2 population variances with sample sizes of n1 = 8 andn2 = 10, where n1 has the larger variance, the number of degrees of freedom are

Defining and Collecting Data

Organizing and Visualizing Variables

Numerical Descriptive Measures

Basic Probability

Discrete Probability Distributions

The Normal Distribution

Sampling Distributions

Confidence Interval Estimation

Fundamentals of Hypothesis Testing: One-Sample Tests

Chi-Square Tests

Simple Linear Regression

Multiple Regression

Business Analytics

Filters