1. The technique of estimating the next value in a series by taking the weighted average of the current measured value and the previous estimate is sometimes called aging.

Suppose that the estimated time per command for some terminal is T₀. Now suppose its next run is measured to be T₁. We could update our estimate by taking a weighted sum of these two numbers, that is a T₀ + (1-a) T₁

The aging algorithm with a = is being used to predict run times. The previous four runs, from oldest to most recent, are 40, 20, 40, and 15 msec. What is the prediction of the next time?