Daily electricity demand for Victoria, Australia, during 2014 is contained in elecdaily . The data for the rst 20 days can be obtained as follows. a. Plot the data and nd the regression model for...

Daily electricity demand for Victoria, Australia, during 2014 is contained in elecdaily . The data for the rst 20 days can be obtained as follows.

a. Plot the data and nd the regression model for Demand with temperature as an explanatory variable. Why is there a positive relationship?

b. Produce a residual plot. Is the model adequate? Are there any outliers or inuential observations?

c. Use the model to forecast the electricity demand that you would expect for the next day if the maximum temperature was 15 and compare it with the forecast if the with maximum temperature was 35 . Do you believe these forecasts?

d. Give prediction intervals for your forecasts. The following R code will get you started:

e. Plot Demand vs Temperature for all of the available data in elecdaily . What does this say about your model?