Question: The University of Washington (UW) Medical School in Seattle was to evaluate the effectiveness of two different drugs for mental depression. The two drugs selected were Zoloft and Prozac. The UW medical staff selects 325 patients for each medication. For Zoloft it took on the average 13.76 hours to relieve the mental depression. The population standard deviation was known to be 4.54 hours. As for Prozac it took an average of 10.99 hours to relieve the mental depression. The population standard deviation was known to be 5.39 hours. At a seven percent significance level test the claim that Prozac is a more effective medicine than Zoloft in treating mental depression. Assume the population standard deviation is known.