Mark's Ceramics Spent $4000 on a New Kiln Last Year

Essay

Mark's Ceramics spent $4000 on a new kiln last year in the belief that it would cut energy usage 25% over the old kiln. This kiln is an oven that turns "greenware" into finished pottery. Mark is concerned that the new kiln requires extra labor hours for its operation. Mark wants to check the energy savings of the new oven, and also to look over other measures of their productivity to see if the change really was beneficial. Mark has the following data to work with:
Were the modifications beneficial?