Bob Nale is the owner of Nale's Texaco GasTown. Bob would like to estimate the mean number of litres (L) of gasoline sold to his customers. Assume the number of litres sold follows the normal distribution with a standard deviation of 40 L. From his records, he selects a random sample of 29 sales and finds the mean number of litres sold is 89.

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 98% confidence interval for the population mean. (Round the final answers to 3 decimal places.)

The 98% confidence interval for the population mean is between and .

c.Interpret the meaning of part (b).

If 100 such intervals were determined, the population (Click to select) mean variance would be included in about intervals.