In given Exercise, if the sample size had been n = 5 instead of n = 30, what assumption would have to be made about the population distribution of filling weights in order to use z values in constructing the confidence interval?
Exercise
A machine that stuffs a cheese-filled snack product can be adjusted for the amount of cheese injected into each unit. A simple random sample of 30 units is selected, and the average amount of cheese injected is found to be = 3.5 grams. If the process standard deviation is known to be σ = 0.25 grams, construct the 95% confidence interval for μ = the average amount of cheese being injected by the machine.