Fiske Corporation manufactures a popular regional brand of kitchen utensils. The design and variety has been fairly constant over the last three years. The managers at Fiske are planning for some changes in the product line next year, but first they want to understand better the relation between activity and factory costs as experienced with the current products. Discussions with the plant supervisor suggest that overhead seems to vary with labor$-$hours, machine$-$hours, or both. The following data were collected from last three year's operations:

$\backslash$table$[[$Quarter$,$Machine$-$Hours,Labor$-$Hours,Factory costs$],[1,19,750,15,805,$$$3,397,671$