Chapter 8, Hypothesis Testing II Video Solutions, The Essentials of Statistics: A Tool for Social Research

Problem 1

For each of the following, test for the significance of the difference in sample statistics by using the fivestep model. (Hint: Remember to solve Formula $8.4$ before attempting to solve Formula 8.2. Also, in Formula 8.4, perform the mathematical operations in the proper sequence. First, square each sample standard deviation, divide by the proper $N-1$, add the resultant values, and then find the square root of the sum.)

Trinity Steen

Numerade Educator

01:30

Problem 2

Gessner and Healey administered questionnaires to samples of undergraduates. Among other things, the questionnaires contained a scale that measured attitudes toward interpersonal violence (higher scores indicate greater approval of interpersonal violence). Test the results as reported here for sexual, racial, and social-class differences.
a.
b.
c.
d. Summarize your results in terms of the significance and the direction of the differences. Which
of these three factors seems to make the biggest difference in attitudes toward interpersonal violence?

Sarah Howell

Numerade Educator

02:13

Problem 3

Do athletes in different sports vary in terms of intelligence? Reported here are College Board scores of random samples of college basketball and football players. Is there a significant difference? Write a sentence or two explaining the difference.

Eric Goldman

Numerade Educator

00:50

Problem 4

A number of years ago, the road and highway maintenance department of Sin City, Nevada, began recruiting minority group members through an affirmative action program. In terms of efficiency ratings as compiled by their superiors, how do the affirmative action employees rate? The ratings of random samples of both groups were collected, and the results are reported here (higher ratings indicate greater efficiency).
Write a sentence or two of interpretation.

Jennifer Stoner

Numerade Educator

01:28

Problem 5

Are middle-class families more likely than working-class families to maintain contact with kin? Write a paragraph summarizing the results of these tests.
a. A sample of middle-class families reported an average of $7.3$ visits per year with close kin, while a sample of working-class families averaged $8.2$ visits. Is the difference significant?
b. The middle-class families averaged $2.3$ phone calls and $8.7$ e-mail messages per month with close kin. The working-class families averaged $2.7$ calls and $5.7$ e-mail messages per month. Are these differences significant?

Dominador Tan

Numerade Educator

00:24

Problem 6

Are college students who live in dormitories significantly more involved in campus life than students who commute to campus? The following data report the average number of hours per week students devote to extracurricular activities. Is the difference between these randomly selected samples of commuter and residential students significant?

Nick Johnson

Numerade Educator

03:44

Problem 7

Are senior citizens who live in retirement communities more socially active than those who live in age-integrated communities? Write a sentence or two explaining the results of these tests. (Hint:
Remember to use the proper formulas for small sample sizes.)
a. A random sample of senior citizens living in a retirement village reported that they had an average of $1.42$ face-to-face interactions per day with their neighbors. A random sample of those living in age-integrated communities reported $1.58$ interactions. Is the difference significant?
b. Senior citizens living in the retirement village reported that they had an average of $7.43$ telephone calls with friends and relatives each week, while those in the age-integrated communities reported an average of $5.50$ calls. Is the difference significant?

Lucas Finney

Numerade Educator

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Problem 8

As the director of the local Boys \& Girls Club, you have claimed for years that membership in your club reduces juvenile delinquency. A cynical member of your funding agency has demanded proof of your claim. Fortunately, your local sociology department is on your side and springs to your aid with student assistants, computers, and hand calculators at the ready. Random samples of members and nonmembers are gathered and interviewed with respect to their involvement in delinquent activities. Each respondent is asked to enumerate the number of delinquent acts he has engaged in over the past year. The results are in and reported here (the average number of admitted acts of delinquency). What can you tell the funding agency?

Kari Hasz

Numerade Educator

02:34

Problem 9

A survey has been administered to random samples of respondents in each of five nations. For each nation, are men and women significantly different in terms of their reported levels of satisfaction? $\mathrm{Re}$ spondents were asked: "How satisfied are you with your life as a whole?" Responses varied from 1 (very dissatisfied) to 10 (very satisfied). Conduct a test for the significance of the difference in mean scores for each nation.

James Kiss

Numerade Educator

03:01

Problem 10

For each problem, test the sample statistics for the significance of the difference.

Joshua Argo

Numerade Educator

02:29

Problem 11

About half of the police officers in Shinbone, Kansas, have completed a special course in investigative procedures. Has the course increased their efficiency in clearing crimes by arrest? The proportions of cases cleared by arrest for samples of trained and untrained officers are reported here.

Lauren Shelton

Numerade Educator

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Problem 12

A large counseling center needs to evaluate several experimental programs. Write a paragraph summarizing the results of these tests. Did the new programs work?
a. One program is designed for divorce counseling; the key feature of the program is its counselors, who are married couples working in teams. About half of all clients have been randomly assigned to this special program and half to the regular program, and the proportion of cases that eventually ended in divorce was recorded for both. The results for random samples of couples from both programs are reported here. In terms of preventing divorce, did the new program work?
b. The agency is also experimenting with peer counseling for depressed children. About half of all clients were randomly assigned to peer counseling. After the program had run for a year, a random sample of children from the new program was compared with a random sample of children who did not receive peer counseling. In terms of the percentage of children who were judged to be "much improved," did the new program work?

Rashmi Sinha

Numerade Educator

03:01

Problem 13

SOC At St. Algebra College, the sociology and psychology departments have been feuding for years about the respective quality of their programs. In an attempt to resolve the dispute, you have gathered data about the graduate school experience of random samples of both groups of majors. The results are presented here: the proportion of majors who applied to graduate schools, the proportion of majors accepted into their preferred programs, and the proportion of these who completed their programs. As measured by these data, is there a significant difference in program quality?
a. Proportion of majors who applied to graduate school:
b. Proportion accepted by program of first choice:
c. Proportion completing the programs:

Andy Wong

Numerade Educator

02:30

Problem 14

The mayor of Sin City, Nevada, started a "crimeline" program some years ago and wonders if it is really working. The program publicizes unsolved violent crimes in the local media and offers cash rewards for information leading to arrests. Are "featured" crimes more likely to be cleared by arrest than other violent crimes? Results from ran-
dom samples of both types of crimes are reported as follows:

Sheryl Ezze

Numerade Educator

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Problem 15

Some results from a survey administered to a nationally representative sample are reported here in terms of differences by sex. Which of these differences, if any, are significant? Write a sentence or two of interpretation for each test.
a. Proportion favoring the legalization of marijuana:
b. Proportion strongly agreeing that "kids are life's greatest joy":
c. Proportion voting for President Obama in 2008 :
d. Average hours spent with e-mail each week:
e. Average rate of church attendance: (number of times per year)
f. Number of children:

Rashmi Sinha

Numerade Educator

01:05

Problem 16

A researcher is studying the effects of the college experience on attitudes, values, and behaviors and is comparing random samples of freshmen and seniors at the same university. Which of the following differences are significant?
a. Proportion calling parents at least once a day:
b. Proportion with a "close friend" from another racial or ethnic group:
c. Proportion saying that they are "very interested" in national politics:
d. Average score on a scale that measures political ideology. On this scale, 10 means "very conservative" and 1 means "very liberal."
e. Average score on a scale that measures support for traditional gender roles. This scale ranges from 7 ("Very traditional") to 1 ("Very nontraditional").

Harsh Gadhiya

Numerade Educator