8.9 For the mc oppe.r data:

(a) if necessary, find a suitable Box-Cox transformation for the data;

(b) fit a suitable ARIMA model to the transformed data using auto. arima ();

(c) try some other plausible models by experimenting with the orders chosen;

(d) choose what you think is the best model and check the residual diagnostics;

(e) produce forecasts of your fitted model. Do the forecasts look reasonable?

(f) compare the results with what you would obtain using ets () (with no transformation).