Question 1

Repeated measurements from the same individuals is an example of data collected from two related populations.

Accepted Answer

A) True 
 B)False

Question 2

When the F test is used for ANOVA, the rejection region is always in the right tail.

Accepted Answer

A) True 
 B)False

Question 3

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 null hypothesis should be rejected.

Accepted Answer

A) True 
 B)False

Question 4

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 same decision would be made if this had been a two-tail test at a level of significance of 0.01.

Accepted Answer

A) True 
 B)False

Question 5

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 standardized value of the estimate of the mean of the sampling distribution for the difference between sample means?

Accepted Answer

A) 0.2025 
B) 0.3544 
C) 2.0115 
D) 2.2140 
A) 0.2025 
B) 0.3544 
C) 2.0115 
D) 2.2140

Question 6

The F distribution is symmetric.

Accepted Answer

A) True 
 B)False

Question 7

Which of the following components in an ANOVA table are not additive?

Accepted Answer

A) Sum of squares. 
B) Degrees of freedom. 
C) Mean squares. 
D) It is not possible to tell. 
A) Sum of squares. 
B) Degrees of freedom. 
C) Mean squares. 
D) It is not possible to tell.

Question 8

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, what is the 99% confidence interval estimate for the mean difference in weight before and after the diet?

Accepted Answer

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

Question 9

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 less than the females.Using the test statistic given, compute the appropriate p-value for the test.

Accepted Answer

A) 0.0170 
B) 0.0340 
C) 0.9660 
D) 0.9830 
A) 0.0170 
B) 0.0340 
C) 0.9660 
D) 0.9830

Question 10

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, the p-value for a one-tail test (in the hypothesized direction) is.

Accepted Answer

0.0079 if using PHSt

Question 11

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 Trevor seeds.

Accepted Answer

A) True 
 B)False

Question 12

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, suppose $\alpha$ = 0.05.Which of the following represents the result of the test on a difference in the variabilities of the amount of time required to reach a customer service representative between the two hotels?

Accepted Answer

A) The alternative hypothesis is rejected. 
B) The null hypothesis is rejected. 
C) The null hypothesis is not rejected. 
D) Insufficient information exists on which to decide. 
A) The alternative hypothesis is rejected. 
B) The null hypothesis is rejected. 
C) The null hypothesis is not rejected. 
D) Insufficient information exists on which to decide.

Question 13

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, in testing the null hypothesis that the mean downhill coasting speeds of the 4 brands of bicycles are equal, the value of the test statistic is .

Accepted Answer

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

Question 14

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 value of the test statistic?

Accepted Answer

The answer of SCENARIO 10-15
The table below presents the summary...

Question 15

In testing for differences between the means of 2 related populations where the variance of the differences is unknown, the degrees of freedom are a) $n - 1$.
b) $n _ { 1 } + n _ { 2 } - 1$.
c) $n _ { 1 } + n _ { 2 } - 2$.
d) $n - 2$.

Accepted Answer

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

Question 16

SCENARIO 10-5
A hotel chain has identically small sized resorts in 5 locations in different small islands.The data that follow resulted from analyzing the hotel occupancies on randomly selected days in the 5 locations. $$\begin{array}{l}
\begin{array} { l c c c c c } 
\text { ROW } & \text { Location A } & \text { Location B } & \text { Location C } & \text { Location D } & \text { Location E } \
\hline 1 & 28 & 40 & 21 & 37 & 22 \
2 & 33 & 35 & 21 & 47 & 19 \
3 & 41 & 33 & 27 & 45 & 25
\end{array}\
\text { Analysis of Variance }\
\begin{array} { l r r r c c } 
\hline \text { Source } & d f & \text { SS } & \text { MS } & F & p \
\hline \text { Location } & 4 & 963.6 & & 11.47 & 0.001 \
\text { Error } & 10 & 210.0 & & & \
\hline\text { Total } & & & & & \
\hline
\end{array}
\end{array}$$
-Referring to SCENARIO 10-5, if a level of significance of 0.05 is chosen, the decision made indicates that all 5 locations have different mean occupancy rates.

Accepted Answer

A) True 
 B)False

Question 17

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 value of the sample mean difference is if the difference scores reflect the results of the exam after the course minus the results of the exam before the course.

Accepted Answer

A) 0 
B) 50 
C) 68 
D) 400 
A) 0 
B) 50 
C) 68 
D) 400

Question 18

In testing the difference between two proportions using the normal distribution, you may use a two-tail Z test.

Accepted Answer

A) True 
 B)False

Question 19

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, the computed t statistic is .

Accepted Answer

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

Question 20

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. $\begin{array}{ll}
\text { A: } 1.2,1.1,0.9,0.4 & \text { C: } 1.0,1.5,1.1,1.3 \
\text { B: } 2.5,2.1,1.9,1.6 & \text { D: } 0.8,1.3,1.1,0.7
\end{array}$
Interpret the results of the analysis summarized in the following table:
$\begin{array}{lcclcc}
\hline\text { Source } & \text { df } & \text { SS } & \text { MS } & \text { F } & \text { PR }>\text { F } \
\hline \text { Neighborhoods } & & 3.1819 & 1.0606 & 10.76 & 0.001 \
\text { Error } & 12 & & & &\
\hline\text { Total }&&4.3644
\end{array}$
-Referring to SCENARIO 10-2, what should be the decision for the Levene's test for homogeneity of variances at a 5% level of significance?

Accepted Answer

A) Reject the null hypothesis because the p-value is smaller than the level of significance. 
B) Reject the null hypothesis because the p-value is larger than the level of significance. 
C) Do not reject the null hypothesis because the p-value is smaller than the level of significance. 
D) Do not reject the null hypothesis because the p-value is larger than the level of significance. 
A) Reject the null hypothesis because the p-value is smaller than the level of significance. 
B) Reject the null hypothesis because the p-value is larger than the level of significance. 
C) Do not reject the null hypothesis because the p-value is smaller than the level of significance. 
D) Do not reject the null hypothesis because the p-value is larger than the level of significance.

Repeated measurements from the same individuals is an example of data collected from two related populations.

When the F test is used for ANOVA, the rejection region is always in the right tail.

The F distribution is symmetric.

Which of the following components in an ANOVA table are not additive?

In testing for differences between the means of 2 related populations where the variance of the differences is unknown, the degrees of freedom are a) $n - 1$ . b) $n _ { 1 } + n _ { 2 } - 1$ . c) $n _ { 1 } + n _ { 2 } - 2$ . d) $n - 2$ .

In testing the difference between two proportions using the normal distribution, you may use a two-tail Z test.

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

Exam 10: Two-Sample Tests

Repeated measurements from the same individuals is an example of data collected from two related populations.

When the F test is used for ANOVA, the rejection region is always in the right tail.

The F distribution is symmetric.

Which of the following components in an ANOVA table are not additive?

In testing for differences between the means of 2 related populations where the variance of the differences is unknown, the degrees of freedom are a) n−1n - 1n−1 . b) n1+n2−1n _ { 1 } + n _ { 2 } - 1n1​+n2​−1 . c) n1+n2−2n _ { 1 } + n _ { 2 } - 2n1​+n2​−2 . d) n−2n - 2n−2 .

In testing the difference between two proportions using the normal distribution, you may use a two-tail Z test.

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

In testing for differences between the means of 2 related populations where the variance of the differences is unknown, the degrees of freedom are a) $n - 1$ . b) $n _ { 1 } + n _ { 2 } - 1$ . c) $n _ { 1 } + n _ { 2 } - 2$ . d) $n - 2$ .