Bob Nale is the owner of Nale's Quick Fill. Bob would like to estimate the mean number of gallons of gasoline sold to his customers. Assume the number of gallons sold follows the normal distribution with a population standard deviation of 1.80 gallons. From his records, he selects a random sample of 80 sales and finds the mean number of gallons sold is 6.90.
Determine a 95% confidence interval for the population mean