Question 1

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  True

Question 2

The t test for the mean difference between 2 related populations assumes that the

Accepted Answer

A) population sizes are equal. 
B) sample variances are equal. 
C) population of differences is approximately normal, or sample sizes are large enough. 
D) All of the above. 
A) population sizes are equal. 
B) sample variances are equal. 
C) population of differences is approximately normal, or sample sizes are large enough. 
D) All of the above. C

Question 3

SCENARIO 10-3
A real estate company is interested in testing whether the mean time that families in Gotham have been living in their current homes is less than families in Metropolis.Assume that the two population variances are equal.A random sample of 100 families from Gotham and a random sample of 150 families in Metropolis yield the following data on length of residence in current homes.
   Gotham:
 $$\bar { X } _ { \mathrm { G } } = 35 \text { months, } \quad S _ { \mathrm { G } } { } ^ { 2 } = 900 \quad \text { Metropolis: } \quad \bar { X } _ { \mathrm { M } } = 50 \text { months, } \mathrm { S } _ { \mathrm { M } } { } ^ { 2 } = 1050$$  
-Referring to Scenario 10-3, what is the 95% confidence interval estimate for the difference in the two means?

Accepted Answer

-23.00 to-7.00 months

Question 4

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 null hypothesis should be rejected at 0.005 level of significance.

Accepted Answer

A) True 
 B)False

Question 5

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, if the buyer had decided to perform a two-tail test, the p-value would have been .

Accepted Answer

0.16 if using PHStat

Question 6

For all two-sample tests, the sample sizes must be equal in the two groups.

Accepted Answer

A) True 
 B)False

Question 7

When testing $$H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } \geq 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } < 0$$ , the observed value of the Z test statistic was found to be - 2.13.The p-value for this test is

Accepted Answer

A) 0.0166. 
B) 0.0332. 
C) 0.9668. 
D) 0.9834. 
A) 0.0166. 
B) 0.0332. 
C) 0.9668. 
D) 0.9834.

Question 8

In a one-way ANOVA, the null hypothesis is always

Accepted Answer

A) there is no difference in the population means. 
B) there is some treatment effect. 
C) all the population means are different. 
D) some of the population means are different. 
A) there is no difference in the population means. 
B) there is some treatment effect. 
C) all the population means are different. 
D) some of the population means are different.

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, construct a 95% confidence interval estimate of the difference between the proportion of males and females who prefer Pepsi.

Accepted Answer

The answer of SCENARIO 10-8
A few years ago, Pepsi invited...

Question 10

The MSE must always be positive.

Accepted Answer

A) True 
 B)False

Question 11

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, what are the numerator and denominator degrees of freedom forLevene's test for homogeneity of variances respectively?

Accepted Answer

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

Question 12

A completely randomized design

Accepted Answer

A) has only one factor with several treatment groups. 
B) can have more than one factor, each with several treatment groups. 
C) has one factor and one block. 
D) has one factor and one block and multiple values. 
A) has only one factor with several treatment groups. 
B) can have more than one factor, each with several treatment groups. 
C) has one factor and one block. 
D) has one factor and one block and multiple values.

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, construct a 90% confidence interval estimate of the difference in proportion between the Kohler and Russell flash drives that are defective.

Accepted Answer

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

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, what is the 90% confidence interval estimate for the mean difference in prices?

Accepted Answer

The answer of SCENARIO 10-7
A buyer for a manufacturing plant...

Question 15

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(are) the critical value(s) of the relevant hypothesis test if the level of significance is 0.10?

Accepted Answer

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

Question 16

SCENARIO 10-1
Are Japanese managers more motivated than American managers? A randomly selected group of each were administered the Sarnoff Survey of Attitudes Toward Life (SSATL), which measures motivation for upward mobility.The SSATL scores are summarized below. $$\begin{array} { l l l } 
& \text { American } & \text { Japanese } \
\text { Sample Size } & 211 & 100 \
\text { Sample Mean SSATL Score } & 65.75 & 79.83 \
\text { Sample Std. Dev. } & 11.07 & 6.41
\end{array}$$
-Referring to Scenario 10-1, find the p-value if we assume that the alternative hypothesis was a two-tail test.

Accepted Answer

A) Smaller than 0.01 
B) Between 0.01 and 0.05 
C) Between 0.05 and 0.10 
D) Greater than 0.10 
A) Smaller than 0.01 
B) Between 0.01 and 0.05 
C) Between 0.05 and 0.10 
D) Greater than 0.10

Question 17

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 conclusion for the Levene's test for homogeneity of variances at a 5% level of significance?

Accepted Answer

A) There is insufficient evidence that the variances are all the same. 
B) There is sufficient evidence that the variances are all the same. 
C) There is insufficient evidence that the variances are not all the same. 
D) There is sufficient evidence that the variances are not all the same. 
A) There is insufficient evidence that the variances are all the same. 
B) There is sufficient evidence that the variances are all the same. 
C) There is insufficient evidence that the variances are not all the same. 
D) There is sufficient evidence that the variances are not all the same.

Question 18

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 two-tail test is _.

Accepted Answer

0.016 if using PHSta

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, the decision made implies that all 4 means are significantly different.

Accepted Answer

A) True 
 B)False

Question 20

In a one-way ANOVA

Accepted Answer

A) an interaction term is present. 
B) an interaction effect can be tested. 
C) there is no interaction term. 
D) the interaction term has (c - 1)(n - 1)degrees of freedom. 
A) an interaction term is present. 
B) an interaction effect can be tested. 
C) there is no interaction term. 
D) the interaction term has (c - 1)(n - 1)degrees of freedom.

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

The t test for the mean difference between 2 related populations assumes that the

For all two-sample tests, the sample sizes must be equal in the two groups.

When testing $H _ { 0 } : \pi _ { 1 } - \pi _ { 2 } \geq 0 \text { versus } H _ { 1 } : \pi _ { 1 } - \pi _ { 2 } < 0$ , the observed value of the Z test statistic was found to be - 2.13.The p-value for this test is

In a one-way ANOVA, the null hypothesis is always

The MSE must always be positive.

A completely randomized design

In a one-way ANOVA

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

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

The t test for the mean difference between 2 related populations assumes that the

For all two-sample tests, the sample sizes must be equal in the two groups.

In a one-way ANOVA, the null hypothesis is always

The MSE must always be positive.

A completely randomized design

In a one-way ANOVA

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