Listed below are statistics from seven baseball teams. The statistics consist of the proportions of wins and the result of this difference: Difference = (number of runs scored) - (number of runs allowed) for a recent year. Find the best predicted winning proportion for San Diego, which has a difference of 52 runs. Is the predicted proportion close to the actual proportion of 0.543?

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.

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Difference Wins 163 55 -5 0.599 0.537 0.531 0.481 88 51 0.494 16 0.506 -214 0.383 Yes. The regression equation is a good model. 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. Substitute the given value of x into the regression equation ŷ = b + b₁x. No. The regression equation is not a good model. Regardless of the value of x, the best predicted value of y is the value of y (the mean of the y values). Figure 10-5 Recommended Strategy for Predicting Values of y