Question: If you're not sure, call Dumbledore!

The OD manager of an East Bay firm wants to determine whether an amount of magic motivational elixir contained in 1-gallon cans purchased from a magicians' cooperative actually averages one gallon. It is known from the magicians' specifications that the standard deviation of the amount of paint is equal to .02 gallon. In her research of this problem, the OD manager chooses a random sample of 50 cans from the shipment, and finds that the mean amount of elixir per 1-gallon can is .995 gallon.

a. State the null hypothesis. What is the research hypothesis?

b. With p = .05, determine if there is evidence from the sample of elixir cans that the magic cooperative is cheating customers. Explain your conclusion.