QNo.4: The U.S. Dairy Industry wants to estimate the mean yearly milk consumption. A sample of 16 people reveals the mean yearly consumption to be 60 gallons with a standard deviation of 20 gallons. What is the value of the population mean? What is the best estimate of this value? Explain why we need to use the t distribution. What assumption do you need to make? For a 90 percent confidence interval, what is the value of t? Develop the 90 percent confidence interval for the population mean. Would it be reasonable to conclude that the population mean is 63 gallons?
QNo.5: At the time she was hired as a server at the Grumney Family Restaurant, Beth Brigden was told, "You can average $80 a day in tips." Assume the population of daily tips is normally distributed with a standard deviation of $3.24. Over the first 35 days she was employed at the restaurant, the mean daily amount of her tips was $84.85. At the 0.01 significance level, can Ms. Brigden conclude that her daily tips average more than $80?