Required (a) Using the high-low method estimate a cost function for shipping expenses. (b) Using regression analysis, estimate a cost function for shipping expenses. (c) What percentage of the variation in shipping expenses is explained by the variation in units shipped? (d) What is your best estimate of the shipping expenses to be incurred in August if the plan is to ship 1 unit in that month? (e) What factors, other than the number of units shipped is likely to affect the company's total shipping expenses? Explain