According to a recent survey, americans get a mean of 7 hours of sleep per night. a random sample of 50 students at west virginia university revealed the mean length of sleep last night was 6 hours and 48 minutes (6.8 hours). the standard deviation of the sample was 0.9 hour. at the 5% level of significance, it is reasonable to conclude students at west virginia sleep less than the typical american? compute the p-value