Korner Hardware manager Emerson Jones is interested in determining how many nativity scenes to order for the 12-day holiday season. Past experience indicates that demand for these nativity scenes averages nine per day during this 12-day period, with a standard deviation of three per day. Demand is approximately normal. Emerson purchases the nativity scenes for $24 per unit and sells them for $48 each during the season. After Christmas, they are marked down as sale items for $16 each. How many units should Emerson order for the coming holiday season?