The average length of "short hospital stays" for men is slightly longer than that for women, 5.6 days versus 4.7 days. A random sample of recent hospital stays for both men and women revealed the following. The goal of the study is to determine if there is sufficient evidence to conclude, at a = 0.1, that the average hospital stay for men is longer than the average hospital stay for women. Men Women Sample size 38 8 Sample mean 5.6 days 4.7 days Population standard deviation 1.3 days 1.7 days What would be the critical value(s). 1.28 O +1.28 O 1.65 O +1.65