A random sample of 25 customers at the checkout in a small local supermarket revealed that they had spent the following amounts in the supermarket ($):
25 45505963538054 1218272930
65501572437160355549 15 54
(a) Give a point estimate for the mean amount per customer spent at the supermarket.
(b) Give a 99% confidence interval estimate for the mean amount per customer spent at the supermarket.