Please provide excel formulas

Question 4: Cool Breeze sells a particular model of fan, with most of the sales being made in the summer months. The store makes a one-time purchase of the fans prior to each summer season at a cost of $40 each and sells each fan for $60. Any fans unsold at the end of the summer season are marked down to $29 and are sold in a special fall sale. The store has never had a problem in the past selling these fans at the markdown price in the fall. The following list represents the number of fans demanded during the past 10 summers: 30, 50, 30, 60, 10, 40, 30, 30, 20, 40. a. Based on the observed 10 values of past demand, construct an empirical distribution of summer demand and determine the optimal number of fans for Cool Breeze to purchase in advance of the summer selling season. [10 points) b. The mean of the empirical distribution of past demand values is 34 with a standard deviation of 13.56. Now assume that demand follows a normal distribution with this same mean and standard deviation. Determine the optimal number of fans for Cool Breeze to purchase under this demand distribution. (5 points) c. Based on your results, would you say that the normal distribution provides an adequate approx- imation to the empirical data? Why or why not? (5 points)