A Mail-Order Business Prides Itself in Its Ability to Fill

Short Answer

A mail-order business prides itself in its ability to fill customers' orders in less than six calendar days, on average. Periodically, the operations manager selects a random sample of customer orders and determines the number of days required to fill the orders. On one occasion when a sample of 39 orders was selected, the average number of days was 6.65 with a population standard deviation of 1.5 days. Calculate the appropriate test statistic to test the hypotheses.