Statistics - Hypothesis Testing Projects

You are interested in assessing the effectiveness of a domestic violence counseling program designed to

You are interested in assessing the effectiveness of a domestic violence counseling program designed to decrease the number of domestic abuse incidents among convicted abusers. The case files of ten offenders are randomly selected from the population of convicted abusers. The number of abuse incidents (verbal or physical) six reported six months before the implementation of the counseling program and six months following the completion of the program are reported below. Using a .01 level of significance, test the hypothesis that the number of abuse incidents was greater before participation in the counseling program.
Number of Abuse Incidents Before and After Implementation of Domestic Violence Counseling Program

Offender number	Before	After
1	4	2
2	3	1
3	1	1
4	4	0
5	1	2
6	3	1
7	4	3
8	4	2
9	4	2
10	2	0

You have been hired by the mayor of a mid-sized city who wants to see if senior citizens and younger citizens differ in their attitudes toward a neighborhood watch program. Fifteen citizens from each age group were randomly selected to give their opinions about the effectiveness of the program on a 7-point scale (the higher the number, the more favorable the attitude). Using the data below, test the hypothesis that there is no difference between the two groups of citizens.

Younger Citizens	Senior Citizens
5	3
5	4
7	5
7	7
7	4
6	4
7	3
6	4
5	4
7	3
5	5
7	4
6	2
7	3
6	2

A researcher undertakes a study of physical force incidences among a sample of correctional officers. The research is specifically interested in determining whether the use of force differs depending on the height of the officer. The researcher selected a random sample of 45 officers in three different height categories and examines the number of times each of those officers used physical force within the past 12 months. Use the data below to answer the following questions:

Test the hypothesis that there is a significant difference, overall, between the three height groups and display the means in a bar graph. (30)
Using a post hoc analysis, write where the specific differences are between each of the possible pairwise comparisons of officers’ height. (7)
Calculate the effect size for height (3)

Based on all of these results, would you make any recommendations to your state department of corrections regarding the hiring of correctional officers? Why or why not? (5)

5’0" – 5’10" (X ₁ )	5’11" – 6’4" (X ₂ )	Over 6’4" (X ₃ )
0	3	4
3	3	5
1	1	6
1	2	2
0	4	3
2	3	4
2	5	5
0	1	6
2	2	8
0	0	7
2	1	2
1	2	1
3	0	3
1	3	5
2	2	3

Susan spent $1500 for a weekend seminar entitled "UBFED" designed to help criminal justice graduates obtain a position in federal law enforcement. It’s promotional literature claimed that seminar graduates outperform other CJ grads on federal civil service exams. Susan took the civil service exam for the FBI and did not do well. She has filed a lawsuit against the company behind the UBFED seminar claiming false advertising. In Susan’s seminar class, 20 other graduates took the FBI exam. Using the Freedom of Information Act, Susan learns that the overall mean of all FBI applicants on the civil service exam was 82.50. She also obtained the exam scores of the 20 applicants who took the UBFED seminar. The data is located in the ‘UBFED’ data file. Test UBFED’s claim that their graduates will do better than the average exam score.