Question

A friend of mine does program evaluations for counseling centers that deal with juvenile delinquents. As such, he does many simple statistical analyses that compare some “pre-intervention” behavioral trait to that of the behavioral trait “post-intervention”. For example, say that some intervention is aimed at reducing aggression in adolescent boys. My friend might then quantify pre-intervention aggression (also known as “baseline” aggression) by administering something like The Aggression Scale developed by Orpinas and Frankowski (2001), which yields a value between 0 and 66, with greater numbers indicating higher aggression. Then, after the adolescent boys complete the intervention program, my friend would then again administer The Aggression Scale to determine the effects of the intervention program on aggression (i.e., “post-intervention”). The data might look something like in the below table:

Participant	Pre-Intervention Aggression	Post-Intervention Aggression
1	35	29
2	42	41
3	45	43
4	39	27
5	45	40
6	43	34

Using the above data, answer the following questions (each question is worth 1.67 pts):

Which type of t-test (one-sample, independent samples, related samples) is appropriate for determining if aggression decreased from pre-intervention to post-intervention? Why?

Using the squared point-biserial correlation coefficient, how much of the variance in aggression scores does the intervention account for?

Answer 1

ANSWER:-

1.Which type of t-test is appropriate:-

• For the given situation, a related examples t-test is fitting for deciding whether animosity diminished from pre-mediation to post-intercession, since perceptions are matched and there is coordinated connection between the pre and post intercession hostility scores.
• Tests are connected or subordinate.

2.calculation of variance in aggression scores does the intervention account:-

• For given information, the connection coefficient between the two factors pre intercession animosity and post mediation hostility is given as 0.8163.
• The squared point bi sequential relationship coefficient is given as

R^2 = (0.8163)(0.8163)

= 0.6663.

% = 0.6663*100

% value = 66.63%

• This implies about 66.63% of the fluctuation in hostility scores does the intercession represent.