A bicycle shop plans to offer two specially priced children's models at a sidewalk sale. The basic model will return a profit of $130 and the deluxe model $180. Past experience indicates that sales of the basic model will have a mean of 5.5 bikes with a standard deviation of and sales of the deluxe model will have a mean of 3.6 bikes with a standard deviation of 0.9 bikes. The cost of setting up for the sidewalk sale is $300. a. What are the mean and standard deviation of the net profit? b. What assumptions did you make in calculating them