18. A researcher wanted to see if giving a selective serotonin reuptake inhibitor (anti depressant) would decrease the number of self-injurious behaviors (SIB's) found in adolescents. They gave the anti depressant to a group of 8 participants and counted the numbers of SIBs a person performed for a month after taking the drug for 6 months. Here are the number of SIB'S performed by the 8 people, 27, 25, 32, 40, 43, 37, 35, 38. a. Find the mean variance, and standard deviation of this sample. b. Suppose the =45 and a population SD=5, what is thez score? c. What is the SEM for this particular sample?

19. Going from question 18 another researcher thought giving another anti depressant would have better effects for patients with SIB issues. They ran the same experimental method with n=8 and the results were 30, 32, 35, 38, 35, 31, 33, 34 a. In words what is the difference between these results and those from question 18? b. Should the results in this question make a smaller or larger SEM than in question 18?