2 Section 4.2 #10 & Section 8.2 #38
4.2
10. Determine whether the statement is true or false. If the statement is false, rewrite it as a true
statement. In general, the slope of the least-squares regression line is equal to the correlation
coefficient.
8.2
38. Sleeping outlier: A simple random sample of eight college freshmen were asked how many hours
of sleep they typically got per night. The results were:
7.5 8.0 6.5 24 8.5 6.5 7.0 7.5
Notice that one joker said that he sleeps 24 hours a day.
a. The data contain an outlier that is clearly a mistake. Eliminate the outlier, then construct a 95%
confidence interval for the mean amount of sleep from the remaining values.
b. Leave the outlier in and construct the 95% confidence interval. Are the results noticeably
different? Explain why it is important to check data for outliers.
