Wastewater and electricity. Refer to the daily electricity consumption/supply and wastewater volume on Dillman Road for each of the first five days of each month of 2020, Exercise 2.26 (p. 77). The data consists of 60 days’ billed electricity consumption in kilowatt-hours (kWh), solar supply in kilowatt-hours (kWh), total supply in kilowatt-hours (kWh), daily peak electricity demand in kilowatts (kW), and volume of wastewater in million gallons (MG). The first five observations are listed in the accompanying table.

a. Propose a straight-line model relating billed electricity consumption (y) to the total supply (x).

b. Fit the model to the data using the method of least squares.

c. Interpret the least squares estimates of the slope and y-intercept in the words of the problem.

d. Statistically assess the adequacy of the model. Do you recommend using it to predict billed electricity consumption?