12. Finding Prediction Interval For a given tar amount of 17 mg, identify the 95% prediction interval estimate of the amount of nicotine, and write a statement interpreting that interval.

Finding Measures of Variation. In Exercises 13–16, find the

(a) explained variation, (b)

unexplained variation,

(c) total variation,

(d) coefficient of determination, and

(e) standard error of estimate se. In each case, there is a linear correlation so that it is reasonable to use the regression equation when making predictions. (Results are used in Exercises 17–20.)