15. The following probabilities are for fruit boxes sold by Sam and Co. every month. From the past sales records, the company has recorded the following sales numbers and probabilities. Compute the expected number of fruit boxes that will be sold next month. NUMBER OF BOXES PROBABILITY 0.20 10 0.30 15 0.40 25 0.10 a. Using Excel, calculate the expected number of boxes. b. Using Excel, find the standard deviation for the distribution