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48 Managerial Accounting for Managers, 4th Edition
Case 2-27 (continued)
3. The number of paid days should be used as the activity base rather than
the number of units produced. The scattergraphs reveal a much
stronger relation (i.e., higher correlation) between direct labor costs and
number of paid days than between direct labor costs and number of
units produced. Variations in the direct labor costs apparently occur
because of the number of paid days in the month and have little to do
with the number of units that are produced. It appears that the direct
labor costs are basically fixed with respect to how many units are
produced in a month. This would happen if the direct labor workers are
treated as full-time employees who are paid even if there is insufficient
work to keep them busy. Moreover, for planning purposes, the company
is likely to be able to predict the number of paid days in the month with
much greater accuracy than the number of units that will be produced.