Predicting future outputs — machine learning
In machine learning, the emphasis
is rather on predicting some (not yet seen) output y*? for some new input x* = [x*1 x*2 . . . x*p ] T. To make a prediction for a test input x* , we insert it into the model (1). Since ε (by assumption) has mean value zero, we take the prediction as
We use the symbol ^ on y * to indicate that it is a prediction, our best guess. If we were able to somehow observe the actual output from x *, we would denote it by y * (without a hat).