Use the CPI / subway fare data from the preceding exercise and find the best predicted subway fare for a time when the CPI reaches 500. What is wrong with this prediction?
In each case, find the regression equation, letting the first variable be the predictor (x) variable. Find the indicated predicted value by following the prediction procedure summarized in Figure 10-5 on page 493.
Figure 10-5

Strategy for Predicting Values of y Is the regression equation a good model? The regression line graphed in the scatterplot shows that the line fits the points well. r indicates that there is a linear correlation. The prediction is not much beyond the scope of the available sample data. Yes. The regression No. The regression equation is not a good model. equation is a good model. Substitute the given v into the regression equation alue of X Regardless of the value of x, the best predicted value of y is the value of y (the mean of the y values)