A random sample of size 15 taken from a normally distributed population revealed a mean of 75 and a variance of 25. The upper limit of a 95% confidence interval for the population mean would equal:

O 88.85 O 77.77 O 87.65 O 77.27

A Car wash owner is interested in estimating the average amount its money its luxury car customers spent on their Cars. 15 car owners were randomly sampled and analyzed with the following results: # = $30.50 and std dev = 13. A 95% confidence interval for the average amount spent in the car wash is:

O $30.50 + $7.20. O $30.50 + $5 91. O $30.50 + $6 58. O $30.50 $5.52.