A firm has been using the following equation to predict annual demand for helix gears:
yt = 55 + 4t,
where t is in years.
Thus, for example, the prediction for year 2 is 55 + 4*2 = 63 Actual demand for the past few years is shown below.
Year 2 3 4 5 6 7
Demand 60 65 69 76 85 85
Based on the data supplied is the forecasting model performing as well as it might? Support your answer quantitatively!