32. Exercise 16 of Section 12.2 gave data on x
rainfall volume and y
runoff volume (both in m3

). Use the accompanying MINITAB output to decide whether there is a useful linear relationship between rainfall and runoff, and then calculate a confidence interval for the true average change in runoff volume associated with a 1-m3 increase in rainfall volume.

The regression equation is runoff
1.13 0.827 rainfall Predictor Coef Stdev t-ratio p Constant 1.128 2.368 0.48 0.642 rainfall 0.82697 0.03652 22.64 0.000 s
5.240 R-sq
97.5% R-sq(adj)
97.3%