In a fictional study, a pretest-posttest design was used to examine the influence of a television program on children's aggressiveness. The number of aggressive responses was measured during an observation period both before and after the television program.
Please refer to Table: TV and Aggressiveness in below.
(a) Determine if there is a difference in the number of aggressive behaviors in children after having viewed the television program, using a 95% confidence interval.
(b) Compute Cohen's d as a measure of effect size and interpret its meaning.
Table: TV and Aggressiveness
Participant Before After
1 6 9
2 4 3
3 8 11
4 9 12
5 10 14
6 2 6
7 14 13