
42. Cost Forecast Modeling. Elliot Ness, manager of product packaging at Chicago Tool & Die, Inc., is
evaluating the cost effectiveness of the preventive maintenance program in his department. Ness believes that
the monthly downtime of the packaging line due to equipment breakdown is related to the hours spent each
month on preventive maintenance.
Write an equation to predict next month's downtime using the symbols D = downtime, M = preventive maintenance, t = time, a0 =
constant term, a1 = regression slope coefficient, and assuming that downtime in the forecast month decreases by the same percentage as
preventive maintenance increased during the preceding month.
43. Cost Forecast Modeling. Robert Romano, CEO of Rocket Science, Inc., is evaluating the cost effectiveness
of the preventive maintenance program. Romano believes that the monthly downtime of the accelerator line due
to equipment breakdown is related to the hours spent each month on preventive maintenance.
Write an equation to predict next month's downtime using the symbols D = downtime, M = preventive maintenance, t = time, a0 =
constant term, a1 = regression slope coefficient, and assuming that downtime in the forecast month decreases by half of the percentage
increase in preventive maintenance during the preceding month.
44. Cost Forecast Modeling. John Carter, an intern at Medical Products, Inc., is evaluating the cost
effectiveness of a training program in his department. Carter believes that the monthly rejection rate is inversely
related to the hours spent each month on worker training.
Write an equation to predict next month's rejection rate using the symbols R = rejection rate, T = worker training, t = time, a0 = constant
term, a1 = regression slope coefficient, and assuming that the rejection rate in the forecast month decreases by twice the percentage
increase in worker training during the preceding month.