PROBLEM I (10 POINTS) Global Publishers has collected the following data for recent months: Month March April May June Issues published 20,500 21,800 17,750 21,200 Total cost $20,960 22,464 18,495 21,395 Required: (a) Using the high-low method, find variable cost per unit, total fixed costs, and the total cost equation. (b) What is the estimated cost for a month in which 19,000 issues are published