5. A random sample of 100 cars in the drive-through of a popular fast-food restaurant revealed an average bill of $96.80 per car. The population standard deviation is $15.20 a. Calculate the margin of error at 99% confidence level. (1 Mark) b. Construct a 99% confidence interval for the population mean. (2 Marks) c. Calculate the sample size at 95% confidence level if the margin of error is 1. (2 Marks)