a simple random sample of nine college freshman were asked how many hours of sleep they typically got per night. The results were 8.5,9, 24, 8. 6.5, 6, 9.5, 7.5,7.5. Notice that one joker said that he sleeps 24 hours a day. The data contain an outlier that is clearly a mistake. Eliminate the outlier, than construct an 80% confidence interval for the mean amount of sleep from the remaining values