A clinical psychologist is studying the effects of an experimental medication on depression. He randomly assigns the next 50 patients at his clinic to receive either

(a) Prozac or

(b) A placebo.

Each patient is treated individually. After eight weeks of treatment, each patient completes an interval-level depression scale. The standard deviations for the two groups are similar and the psychologist believes depression level is normally distributed. The psychologist is planning to use an independent-samples t test to see if there are differences between the two groups at the eight-week mark. Check the assumptions and decide if it is OK to proceed with the planned test.