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): • Calculate standard error of the mean difference and tobt. • Using an alpha of 0.05, what is tcrit? Would you reject or fail to reject the null hypothesis? Why? •

Answer 1

r code is-

r output-

here p-value is less than alpha(0.5)

therefore we rejected null hypothesis.