Hi.  I need a bit of help with forecasting.

For example, if I have been given the following AR(2) model via Excel:  y(t) = .178 + .887y(t-1) + .081y(t-2) + e(t)

If I want to do a forecast, I understand that I would use the last 2 actual data points from the time series to be y(t-1) and y(t-2), but where do i get e(t) to reach the correct result???

[NEAS: The expected value of e(t) for a forecast is zero.]