medical researchers interested in determining the relative effectiveness of two different drug treatments on people with a chronic mental illness established two independent test groups. the first group consisted of 13 people with the illness, and the second group consisted of 9 people with the illness. the first group received treatment 1 and had a mean time until remission of 154 days, with a standard deviation of 7 days. the second group received treatment 2 and had a mean time until remission of 162 days, with a standard deviation of 6 days. assume that the populations of times until remission for each of the two treatments are normally distributed with equal variance. can we conclude,