Twenty depressed patients were randomly assigned to one of two groups as part of a new antidepressant clinical trial. The researchers were careful to follow all of the procedures necessary for a clinical trial and all participants were fully informed about the nature and risks of the study. Participants received either the drug or the placebo (they didn't know which). After three weeks, the following depression scores were analyzed. Scores ranged from 0 - 20 with the higher the score representing greater level of depression.

Anti-D	Placebo
11	6
12	9
15	6
5	9
17	9
14	3
14	10
19	2
15	7
8	6

• 1. What is the null hypothesis in this study?
  2. What is the alternate hypothesis?
  3. What probability should you use and why?
  4. What are the degrees of freedom?
  5. What is your computed answertvalue?
  6. Based on yourtvalue, probability level, degrees of freedom, and critical value, is there a significant difference between the two groups?
  7. Interpret your answer--are there differences between the groups? Based on your results, would you recommend the use of this drug to a depressed family member? Why or why not?
  8. If you have made an error, would it be a Type I or a Type II error? Explain.