1.What are the expected sales if the price of Cadbury equals 15HKD and there is no feature and no display in a specific week? 2.What happens to the sales if the price decreases from 15 to 10HKD ? 3. The marketing manager of Cadbury expects that their sales, in addition to their own price, feature and display, also depend on the prices of competitors, such as Dove and Lindt. Specify a regression model to test the expectations of the marketing manager