In Problem 13.7 on page 470, you used the total staff present and remote hours to predict standby hours stored in Standby. Develop a regression model to predict standby hours that includes total staff present, remote hours, and the interaction of total staff present and remote hours.

a. At the 0.05 level of significance, is there evidence that the interaction term makes a significant contribution to the model?

b. Which regression model is more appropriate, the one used in this problem or the one used in Problem 13.7? Explain.