Tree Circumference and Height The table below lists circumferences (in feet) and the heights (in feet) of trees in Marshall, Minnesota (based on data from “Tree Measurements,”

by Stanley Rice, American Biology Teacher, Vol. 61, No. 9). For the prediction interval, use a circumference of 4.0 ft and use a 99% confidence level. Comment on the range of values in the prediction interval.

Circumference 1.8 1.9 1.8 2.4 5.1 3.1 5.5 5.1 8.3 13.7 5.3 4.9 Height 21.0 33.5 24.6 40.7 73.2 24.9 40.4 45.3 53.5 93.8 64.0 62.7 Variation and Prediction Intervals. In Exercises 17–20, find the

(a) explained variation,

(b) unexplained variation, and

(c) indicated prediction interval. In each case, there is sufficient evidence to support a claim of a linear correlation, so it is reasonable to use the regression equation when making predictions.