434. SafSeal extrudes plastic tamper-proof seals for consumer products. The extruders nun best at a temperature of 68. The plant is equipped with a gas furnace for cold weather and eloctric air conditioners for hot weather. For this reason, the electric usage is seasonal with a peak in the summer months and a drop in the winter months. (a) Using a multiplicative model, estimate the parameters. (b) Forecast the electric usage for each quarter of 1996