Why is the answer for 14 C?

Why is the answer for 15 D?

14. The value of an independent variable from the prior period is referred to as a A. lagged variable.* B. dummy variable. C. predictor variable. D. categorical variable. 15. Demand for a product and the forecasting department's forecast (nave model) for a product are shown below. Compute the mean squared error. A. 2.67 B. 4.67 C. 5.33 D. 8.67