Participants are measured on a 10-point depression scale after taking one oranother of the following drugs for six months: a placebo, a natural herb (St. John's Wort), a tricyclic antidepressant (Elavil), and an SSRI drug (Prozac). The summary results are shown below.

Group	N	mean	variance
placebo	10	9.0	36
St. John's Wort	10	8.0	49
Elavi	10	4.0	35
Prozac	10	3.0	35

We are interested in testing whether, at the significance level = .05, the population variances of scores for the four groups are the same. Assume the normality of scores for four groups.

(a) State the null and alternate hypotheses,

(b) Report the value of the test statistic,

(c) Find the critical value, and

(d) Report your decision regarding the null hypothesis and your conclusion in the context of the problem.