11.12 A study was done to study the effect of ambient temperature x on the electric power consumed by a chemical plant y. Other factors were held constant, and the data were collected from an experimental pilot plant.

y (BTU) x (◦F) y (BTU) x (◦F)

250 27 265 31 285 45 298 60 320 72 267 34 295 58 321 74

(a) Plot the data.

(b) Estimate the slope and intercept in a simple linear regression model.

(c) Predict power consumption for an ambient temperature of 65◦F.