Robert would like to estimate the mean number of litres (L) of Olive Oil sold to his customers. He selects a random sample of 25 sales and finds the mean number of litres sold is 77 with a standard deviation of 32 L. .

a. What is the point estimate of the population mean? (Round the final answer to the nearest whole number.)

The point estimate of the population mean is litres.

b. Develop a 90% confidence interval for the population mean. (Round the final answers to 3 decimal places.)

The 90% confidence interval for the population mean is between and .