Suppose that the Giant Springs Water Co. is bottling 12oz. bottles of water and claim that their standard deviation is less than half an ounce per bottle. If they sample 24 bottles and find the sample standard deviation is 0.54 oz is there claim correct at a=0.005. Assume the variable is normally distributed.

What type of test should be used?
z-test for the mean
t-test for the mean
z-test for the mean
X2-test for the standard deviation