1.A clinical psychologist posits that drug use leads to conduct problems. To test this, he examines whether his adolescent inpatient drug users were elevated in terms of conduct disorder (CD). A sample of 25 was evaluated using a standard measure of CD; they had a mean score of 54. The population mean () for the CD scale is 50 with a standard deviation () of 10. Show calculations for the appropriate test.

1. What are the null and alternative hypotheses?

1. What inferential test did you use? Using an alpha level of .05, determine whether the sample was significantly different from population.

1. Report and interpret an effect size.

1. Given your conclusion in part b, what type of error might you be making?