=+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%