This exercise uses the Tbrate data set in the Ecdat package. In Section 9.16.1, nonseasonal models were

Question:

This exercise uses the Tbrate data set in the Ecdat package. In Section 9.16.1, nonseasonal models were fit. Now use auto.arima to find a seasonal model. Which seasonal model is selected by AIC and by BIC? Do you feel that a seasonal model is needed, or is a nonseasonal model sufficient?