Please put all the formulas.. it's my final so please be accurate

Problem 4 You run a meal kit delivery startup and you need to determine the typical time required for a customer to prepare the meal kit into a meal. The research department takes a random sample of 70 customers and calculates the sample average time spent for the meal preparation x to be 97 minutes and the sample standard deviation s to be 14 minutes. a. Calculate the 99% confidence interval for u, the population mean time for meal preparation. The z- critical value for this interval is za = Zo.01 = Zo.005 = 2.575. 2 2 b. Interpret the confidence interval in words. c. The vice president of research asserts that the mean time for meal preparation is 95 minutes. Do you agree with this? Explain how you know. d. Suppose your company needs a narrower confidence interval, so it can decide whether the recipe testing department needs more staff. Calculate the sample size necessary to estimate the population mean within 1 minute