Testing for population mean.
ATMs must be stocked with enough cash to satisfy customers making withdrawals over an entire weekend. But if too much cash is unnecessarily kept in the ATMs, the bank is foregoing the opportunity of investing the money and earning interest. Suppose that at a particular branch the expected average amount of money withdrawn from ATMs per customer transaction over the weekend is $160 with an expected standard deviation of $30.
State appropriate hypotheses.
If a random sample of 36 customer transactions is examined and the sample average amount withdrawn is $172, is there evidence to believe that the population average withdrawal is no longer $160?
What happens as you use different levels of significance? Different values of the standard deviation?