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MGMT 208 Ch 10

Terms in this set (29)

If we are testing for the difference between the means of two independent populations presuming equal variances with samples of n1 = 20 and n2 = 20, the number of degrees of freedom is equal to

a) 38.
b) 19.
c) 39.
d) 18.
a) 38.
In testing for the differences between the means of two independent populations where the variances in each population are unknown but assumed equal, the degrees of freedom are

a) n1 + n2 - 2.
b) n1 + n2 - 1.
c) n - 1.
d) n - 2.
a) n1 + n2 - 2.
In testing for differences between the means of two independent populations, the null hypothesis is:

a) H0: μ1 - μ2 = 0.
b) H0: μ1 - μ2 < 2.
c) H0: μ1 - μ2 = 2.
d) H0: μ1 - μ2 > 0.
a) H0: μ1 - μ2 = 0.
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.
Referring to Table 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?

a) H1: μfemales < μmales
b) H1: μfemales > μmales
c) H1: μfemales ≠ μmales
d)H1: μfemales =μmales
a) H1: μfemales < μmales
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.
Referring to Table 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. From the analysis in Table 10-2, the correct test statistic is ________.

a) -6610
b) -1.7011
c) -1.3763
d) 0.0898
c) -1.3763
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.
Referring to Table 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. The proper conclusion for this test is:

a) At the α = 0.10 level, there is insufficient evidence to indicate any difference in the mean starting salaries of male and female MBA graduates.
b) At the α = 0.10 level, there is sufficient evidence to indicate a difference in the mean starting salaries of male and female MBA graduates.
c) At the α = 0.10 level, there is sufficient evidence to indicate that females have a lower mean starting salary than male MBA graduates.
d) At the α = 0.10 level, there is sufficient evidence to indicate that females have a higher mean starting salary than male MBA graduates.
c) At the α = 0.10 level, there is sufficient evidence to indicate that females have a lower mean starting salary than male MBA graduates.
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.
Referring to Table 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. What assumptions were necessary to conduct this hypothesis test?

a) The population variances are approximately equal.
b) The samples were randomly and independently selected.
c) Both populations of salaries (male and female) must have approximate normal distributions.
d) All of the above assumptions were necessary.
d) All of the above assumptions were necessary.
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.

Referring to Table 10-2, what is the 90% confidence interval estimate for the difference between two means?
$-14,799.99 to $1,599.99
If we are testing for the difference between the means of two related populations with samples of n1 = 20 and n2 = 20, the number of degrees of freedom is equal to

a) 38.
b) 19.
c) 18.
d) 39.
b) 19.
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.
Referring to Table 10-5, the number of degrees of freedom is

a) 8.
b) 7.
c) 14.
d) 13.
b) 7.
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.
Referring to Table 10-5, the value of the standard error of the difference scores is ________.

a) 22.991
b) 60.828
c) 65.027
d) 14.696
a) 22.991
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.
Males: n =109, pM = 0.422018

Females: n =52, pF = 0.25

pM - pF = 0.172018

Z = 2.11825
Referring to Table 10-8, construct a 90% confidence interval estimate of the difference between the proportion of males and females who prefer Pepsi.
0.05 to 0.30
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 π1 and π2 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 the above paragraph, what is the point estimate for the difference between the two population proportions?

a) 0.22
b) 0.10
c) 0.06
d) 0.15
c) 0.06
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 π1 and π2 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 the above paragraph, what is/are the critical value(s) when performing a Z test on whether population proportions are different if α = 0.05?

a) ±2.08
b) ±1.645
c) -1.96
d) ±1.96
d) ±1.96
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 π1 and π2 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 the above paragraph, what is/are the critical value(s) when testing whether the current population proportion is higher than before if α = 0.05?

a) ±1.645
b) ±1.96
c) +1.96
d) +1.645
d) +1.645
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 π1 and π2 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 the above paragraph, what is the estimated standard error of the difference between the two sample proportions?

a) 0.500
b) 0.055
c) 0
d) 0.629
b) 0.055
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 π1 and π2 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 the above paragraph, what is the value of the test statistic to use in evaluating the alternative hypothesis that there is a difference in the two population proportions?

a) 1.093
b) 0
c) 1.96
d) 4.335
a) 1.093
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 π1 and π2 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 the above paragraph, the company tests to determine at the 0.05 level whether the population proportion has changed from the previous study. Which of the following is correct?

a) Reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has changed over the intervening 10 years.
b) Do not reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has increased over the intervening 10 years.
c) Do not reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has not changed over the intervening 10 years.
d) Reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has increased over the intervening 10 years.
c) Do not reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has not changed over the intervening 10 years.
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.
Preservative I
mean I = 106.4 hours
SI = 10.3 hours

Preservative II
meanII = 96.54 hours
SII = 13.4 hours

Referring to Table 10-14, state the null and alternative hypotheses for testing if the population variances differ for preservatives I and II.

a) H0: σI^2 - σII^2 ≠ 0 versus H1: σI^2 - σII^2 = 0
b) H0: σI2^ - σII^2 ≤ 0 versus H1: σI^2 - σII^2 > 0
c) H0: σI^2 - σII^2 ≥ 0 versus H1: σI^2 - σII^2 < 0
d) H0: σI^2 - σII^2 = 0 versus H1: σI^2 - σII^2 ≠ 0
d) H0: σI^2 - σII^2 = 0 versus H1: σI^2 - σII^2 ≠ 0
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.
Preservative I
mean I = 106.4 hours
SI = 10.3 hours

Preservative II
meanII = 96.54 hours
SII = 13.4 hours

Referring to Table 10-14, what is the value of the test statistic for testing if the population variances differ for preservatives I and II?
1.6925
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.
Preservative I
mean I = 106.4 hours
SI = 10.3 hours

Preservative II
meanII = 96.54 hours
SII = 13.4 hours

Referring to Table 10-14, what assumptions are necessary for testing if the population variances differ for preservatives I and II?

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
d) Both A and B are necessary
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.
Preservative I
mean I = 106.4 hours
SI = 10.3 hours

Preservative II
meanII = 96.54 hours
SII = 13.4 hours

Referring to Table 10-14, what is the critical value for testing if the population variances differ for preservatives I and II at the 5% level of significance?
2.9786, 2.95
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.
Preservative I
mean I = 106.4 hours
SI = 10.3 hours

Preservative II
meanII = 96.54 hours
SII = 13.4 hours

Referring to Table 10-14, what is the largest level of significance at which a test of whether the population variances differ for preservatives I and II will not be rejected?
0.3362, greater than 0.10
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.
Preservative I
mean I = 106.4 hours
SI = 10.3 hours

Preservative II
meanII = 96.54 hours
SII = 13.4 hours

Referring to Table 10-14, suppose α = 0.05. Which of the following represents the result of the relevant hypothesis test?

a) The null hypothesis is not rejected.
b) The null hypothesis is rejected.
c) The alternative hypothesis is rejected.
d) Insufficient information exists on which to make a decision.
a) The null hypothesis is not rejected.
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.
Preservative I
mean I = 106.4 hours
SI = 10.3 hours

Preservative II
meanII = 96.54 hours
SII = 13.4 hours

Referring to Table 10-14, suppose α = 0.05. Which of the following represents the correct conclusion?

a) There is evidence of a difference in the population variances between preservatives I and II.
b) There is evidence that the population variances between preservatives I and II are the same.
c) There is no evidence that the population variances between preservatives I and II are the same.
d) There is no evidence of a difference in the population variances between preservatives I and II.
d) There is no evidence of a difference in the population variances between preservatives I and II.
In a one-way ANOVA, if the computed F statistic is greater than the critical F value you may

a) reject H0 since there is evidence all the means differ.
b) reject H0 since there is evidence that not all the means are different.
c) not reject H0 because a mistake has been made.
d) not reject H0 since there is no evidence of a difference in the means.
b) reject H0 since there is evidence that not all the means are different.
The F test statistic in a one-way ANOVA is

a) MSW/MSA.
b) SSA/SSW.
c) SSW/SSA.
d) MSA/MSW.
d) MSA/MSW.
The degrees of freedom for the F test in a one-way ANOVA are

a) (n - c) and (c - 1).
b) (n - 1) and (c - n).
c) (c - n) and (n - 1).
d) (c - 1) and (n - c).
d) (c - 1) and (n - c).
In a one-way ANOVA, the null hypothesis is always:

a) All the population means are different.
b) There is no difference in the population means.
c) There is some treatment effect.
d) Some of the population means are different.
b) There is no difference in the population means.
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