Refer to the data for Sebolt Wire Company in Problem 5-18.

Required:
1. Using the least-squares regression method, estimate a cost formula for power cost. (Round the variable cost to the nearest cent and the fixed cost to the nearest dollar.)
2. Prepare a table showing the total fixed cost per month and the variable cost per ingot under each of the three methods used in Problems 5-18 and 5-19. Then comment on the accuracy and usefulness of the data derived by each method.