A therapist measures the relationship between a patient's expectations that therapy will be successful and the actual success of the therapy. The following table shows the results of this hypothetical study using a sample of 50 clients.

(a) Compute the phi correlation coefficient.
(b) Using a two-tailed test at a .05 level of significance, state the decision to retain or reject the null hypothesis. Hint: You must first convert r to c2.

Therapy Successful No Totals 8 15 Ves Client expects success No Yes 30 5 20 Totals 27 23