statistics
posted by Jelian .
The U.S. Dairy Industry wants to estimate the mean yearly milk consumption. A sample of 20 people reveals the mean yearly consumption to be 72 gallons with a standard deviation of 15 gallons. What is the 99% confidence interval for the population mean?

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion of .005 to get Z value.
99% = mean ± 2.575 SD