The owner of an online store wants to estimate the average number of items purchased per order. They take a random sample of 36 orders and finds a mean of 2.3 items with a standard deviation of 0.5 items. Assume the conditions are satisfied and do NOT need to be checked.

a) Construct a 90% confidence interval.

b) Interpret your confidence interval.

c) Explain how, if at all, the width of your confidence interval changes if the sample size was increased to 100 orders, holding all else the same.