Many colleges are experiencing financial difficulties because of increasing costs of computer maintenance and services. The dean of a college uses data from 1992 to 2011 and estimates the exponential trend model Costt = aebt from the data
ln Costt = 8.87 + 0.09 t
(a) What is the computer services cost for 2012 and 2013 based on this model?
(b) What is the model's estimate of computer services cost for year 1994 [this is called Back casting (as opposed to forecasting)]?
(c) If actual computer services costs for 2012 and 2013 are $44,700 and $46,800 respectively, what is the average of the percentage forecasting errors of the model.