In many cases the purpose of model fitting is to make predictions about the response
given a value of the predictor.
It is important to remember that making predictions outside
the observed range of the data (known as extrapolation) is risky. It is impossible to be
sure that the fitted relationship extends beyond the observed range.
The Predict Y panel is added to the analysis task pane.
For a Budget of 100 million $ the average retained impressions per week is 64.9
million. The 95% confidence interval (CI) 50.2 to 79.5 million is the uncertainty in the
mean estimate. The 95% prediction interval (PI) 18.2 to 111.6 is the interval we would
expect a single future observations to lie within.
(click to enlarge)