Question 1

A completely randomized design with 4 groups would have 6 possible pairwise comparisons.

Accepted Answer

A) True 
 B)False

Question 2

SCENARIO 10-6
To investigate the efficacy of a diet, a random sample of 16 male patients is selected from a population of adult males using the diet.The weight of each individual in the sample is taken at the start of the diet and at a medical follow-up 4 weeks later.Assuming that the population of differences in weight before versus after the diet follow a normal distribution, the t-test for related samples can be used to determine if there was a significant decrease in the mean weight during this period.Suppose the mean decrease in weights over all 16 subjects in the study is 3.0 pounds with the standard deviation of differences computed as 6.0 pounds.
-Referring to Scenario 10-6, the p-value for a one-tail test is _.

Accepted Answer

0.032 if using PHSta

Question 3

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 same decision would be made with this test if the level of significance had been 0.10 rather than 0.05.

Accepted Answer

A) True 
 B)False

Question 4

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, the null hypothesis that the mean downhill coasting speeds of the4 brands of bicycles are equal will be rejected at a level of significance of 0.05 if the value of the test statistic is greater than _.

Accepted Answer

The answer of SCENARIO 10-3
As part of an evaluation program,...

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, what is/are the critical value(s) when testing whether population proportions are different if $\alpha$ = 0.10?

Accepted Answer

A) $\pm$ 1.645 
B) $\pm$ 1.96 
C) -1.96 
D) $\pm$ 2.08 
A) $\pm$ 1.645 
B) $\pm$ 1.96 
C) -1.96 
D) $\pm$ 2.08

Question 6

SCENARIO 10-4
Two samples each of size 25 are taken from independent populations assumed to be normally distributed with equal variances.The first sample has a mean of 35.5 and standard deviation of 3.0 while the second sample has a mean of 33.0 and standard deviation of 4.0.
-Referring to Scenario 10-4, what is the 90% confidence interval estimate for the difference in the two means?

Accepted Answer

The answer of SCENARIO 10-4
Two samples each of size 25...

Question 7

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 the largest level of significance at which a test on a difference in the variabilities of the amount of time required to reach a customer service representative between the two hotels will not be rejected?

Accepted Answer

0.6789 (using Excel)

Question 8

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 buyer should decide that the primary supplier is

Accepted Answer

A) overcharging because there is strong evidence that this is the case. 
B) overcharging because there is insufficient evidence to prove otherwise. 
C) not overcharging because there is insufficient evidence to prove otherwise. 
D) not overcharging because there is strong evidence to prove otherwise. 
A) overcharging because there is strong evidence that this is the case. 
B) overcharging because there is insufficient evidence to prove otherwise. 
C) not overcharging because there is insufficient evidence to prove otherwise. 
D) not overcharging because there is strong evidence to prove otherwise.

Question 9

SCENARIO 10-4
An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds.She plants 15 fields,
5 with each variety.She then measures the crop yield in bushels per acre.Treating this as a completely randomized design, the results are presented in the table that follows. $\begin{array}{rrrr}
\text { Trial}&\text {  Smith}&\text {  Walsh}&\text {  Trevor }\
1 & 11.1 & 19.0 & 14.6 \
2 & 13.5 & 18.0 & 15.7 \
3 & 15.3 & 19.8 & 16.8 \
4 & 14.6 & 19.6 & 16.7 \
5 & 9.8 & 16.6 & 15.2
\end{array}$
-Referring to SCENARIO 10-4, the among-group variation or SSA is _.

Accepted Answer

The answer of SCENARIO 10-4
An agronomist wants to compare the...

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, suppose  $\alpha$  = 0.10.Which of the following represents the correct conclusion?

Accepted Answer

A) There is not enough evidence that the mean starting annual salaries for individuals entering the public accounting professions is not higher than that of financial planning. 
B) There is not enough evidence that the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning. 
C) There is enough evidence that the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning. 
A) There is not enough evidence that the mean starting annual salaries for individuals entering the public accounting professions is not higher than that of financial planning. 
B) There is not enough evidence that the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning. 
C) There is enough evidence that the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning.

Question 11

SCENARIO 10-4
Two samples each of size 25 are taken from independent populations assumed to be normally distributed with equal variances.The first sample has a mean of 35.5 and standard deviation of 3.0 while the second sample has a mean of 33.0 and standard deviation of 4.0.
-Referring to Scenario 10-4, there are degrees of freedom for this test.

Accepted Answer

The answer of SCENARIO 10-4
Two samples each of size 25...

Question 12

In what type of test is the variable of interest the difference between the values of the observations rather than the observations themselves?

Accepted Answer

A) A test for the equality of variances from 2 independent populations. 
B) A test for the difference between the means of 2 related populations. 
C) A test for the difference between the means of 2 independent populations. 
D) All of the above. 
A) A test for the equality of variances from 2 independent populations. 
B) A test for the difference between the means of 2 related populations. 
C) A test for the difference between the means of 2 independent populations. 
D) All of the above.

Question 13

SCENARIO 10-12
A quality control engineer is in charge of the manufacture of USB flash drives.Two different processes can be used to manufacture the flash drives.He suspects that the Kohler method produces a greater proportion of defects than the Russell method.He samples 150 of the Kohler and 200 of the Russell flash drives and finds that 27 and 18 of them, respectively, are defective.If Kohler is designated as "Group 1" and Russell is designated as "Group 2," perform the appropriate test at a level of significance of 0.01.
-Referring to Scenario 10-12, the null hypothesis will be rejected if the test statistic is _.

Accepted Answer

The answer of SCENARIO 10-12
A quality control engineer is in...

Question 14

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, the researcher was attempting to show statistically that the female MBA graduates have a significantly lower mean starting salary than the male MBA graduates.Which of the following is an appropriate alternative hypothesis?

Accepted Answer

A) $H _ { 1 } : \mu _ { \text {females } } > \mu _ { \text {males } }$ B) $H _ { 1 } : \mu _ { \text {females } } < \mu _ { \text {males } }$ C) $H _ { 1 } : \mu _ { \text {females } } \neq \mu _ { \text {males } }$ D) $H _ { 1 } : \mu _ { \text {females } } = \mu _ { \text {males } }$ A) $H _ { 1 } : \mu _ { \text {females } } > \mu _ { \text {males } }$ B) $H _ { 1 } : \mu _ { \text {females } } < \mu _ { \text {males } }$ C) $H _ { 1 } : \mu _ { \text {females } } \neq \mu _ { \text {males } }$ D) $H _ { 1 } : \mu _ { \text {females } } = \mu _ { \text {males } }$

Question 15

The analysis of variance (ANOVA) tests hypotheses about the population variance.

Accepted Answer

A) True 
 B)False

Question 16

SCENARIO 10-4
An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds.She plants 15 fields,
5 with each variety.She then measures the crop yield in bushels per acre.Treating this as a completely randomized design, the results are presented in the table that follows. $\begin{array}{rrrr}
\text { Trial}&\text {  Smith}&\text {  Walsh}&\text {  Trevor }\
1 & 11.1 & 19.0 & 14.6 \
2 & 13.5 & 18.0 & 15.7 \
3 & 15.3 & 19.8 & 16.8 \
4 & 14.6 & 19.6 & 16.7 \
5 & 9.8 & 16.6 & 15.2
\end{array}$
-Referring to SCENARIO 10-4, based on the Tukey-Kramer procedure with an overall level of significance of 0.01, the agronomist would decide that there is a significant difference between the crop yield of Smith and Walsh seeds.

Accepted Answer

A) True 
 B)False

Question 17

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 point estimate for the difference between the two population proportions?

Accepted Answer

A) 0.06 
B) 0.10 
C) 0.15 
D) 0.22 
A) 0.06 
B) 0.10 
C) 0.15 
D) 0.22

Question 18

The test for the equality of two population variances is based on

Accepted Answer

A) the difference between the 2 sample variances. 
B) the ratio of the 2 sample variances. 
C) the difference between the 2 population variances. 
D) the difference between the sample variances divided by the difference between the sample means. 
A) the difference between the 2 sample variances. 
B) the ratio of the 2 sample variances. 
C) the difference between the 2 population variances. 
D) the difference between the sample variances divided by the difference between the sample means.

Question 19

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 the mean speed for the Tornado brand is significantly different from each of the mean speeds for other brands.

Accepted Answer

A) True 
 B)False

Question 20

SCENARIO 10-6
To investigate the efficacy of a diet, a random sample of 16 male patients is selected from a population of adult males using the diet.The weight of each individual in the sample is taken at the start of the diet and at a medical follow-up 4 weeks later.Assuming that the population of differences in weight before versus after the diet follow a normal distribution, the t-test for related samples can be used to determine if there was a significant decrease in the mean weight during this period.Suppose the mean decrease in weights over all 16 subjects in the study is 3.0 pounds with the standard deviation of differences computed as 6.0 pounds.
-Referring to Scenario 10-6, the computed t statistic is .

Accepted Answer

The answer of SCENARIO 10-6
To investigate the efficacy of a...

A completely randomized design with 4 groups would have 6 possible pairwise comparisons.

In what type of test is the variable of interest the difference between the values of the observations rather than the observations themselves?

The analysis of variance (ANOVA) tests hypotheses about the population variance.

The test for the equality of two population variances is based on

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

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Exam 10: Two-Sample Tests

A completely randomized design with 4 groups would have 6 possible pairwise comparisons.

In what type of test is the variable of interest the difference between the values of the observations rather than the observations themselves?

The analysis of variance (ANOVA) tests hypotheses about the population variance.

The test for the equality of two population variances is based on

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