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 8 people with the illness. the first group received treatment 1 and had a mean time until remission of 176 days, with a standard deviation of 7 days. the second group received treatment 2 and had a mean time until remission of days, with a standard deviation of days. assume that the populations of times until remission for each of the two treatments are normally distributed with equal variance. can we conclude, at the 0.05 level of significance, that the mean number of days before remission after treatment 1, , is greater than the mean number of days before remission after treatment 2, ?