The file contains the amount that a sample of nine customers spent for lunch ($) at a fast-food restaurant
4.20 5.03 5.86 6.45 7.38 7.54 8.46 8.47 9.87
a. Construct a 95% confidence interval estimate for the population mean amount spent for lunch ($) at a fast-food restaurant, assuming a normal distribution.
b. Interpret the interval constructed in (a).