Question: Many researchers have reported that exposure to violence on television can result in increased violent or aggressive behavior in children. To evaluate the effect, a researcher obtains a sample of 8 children in a pre-school setting. The group of children is observed for two hours one afternoon, and the number of violent or aggressive acts is recorded for each child. The following morning the children are shown a video cartoon with several violent and aggressive scenes. That afternoon the children are observed again. Does exposure to violence on television significantly increase children’s violent or aggressive behavior? (a=.01, two tailed)

CHILDREN FIRST OBSERVATION SECOND OBSERVATION

1 10 15

2 10 13

3 20 25
4 16 19
5 10 10
6 15 19
7 14 16
8 11 10

A. Given the statistical null hypothesis and alternative hypothesis

Ho Ha

b. Give the critical value for this testing

c. The obtained value is 3.38. Report the finding formally

d. The mean of the difference scores for this sample is -2.625. the standard error of the mean difference s 0.7778. Construct a 99% confidence interval for the average difference between the two conditions.