15.7 Practice Questions Exercise 15.32 (Categorical Independent Variables) Question 1 of 2 1 O Check My Work 2. O Consider a regression study involving a dependent variable y, a quantitative independent variable 21, and a categorical independent variable with two levels (level 1 and level 2). a. Write a multiple regression equation relating 21 and the categorical variable to y. 1. E(y) = Bo + B121 2. E(y) = Bo + 8212 3. E(y) = Bo + Biz1 + 82 4. E(y) = Bo + B121 + 8272 - Select your answer - V Enter the values of dummy variable 22 that are used to indicate the two levels of the qualitative variable. If your answer is zero, enter "0". Level 1 Level 2 b. What is the expected value of y corresponding to level 1 of the categorical variable? 1. E(y) = Bo + 3121 2. E(y) = Bo + 3272 3. E(y) = Bo + Biz1 + B2 4. E(y) = Bo + B121 + 8272 - Select your answer - v c. What is the expected value of y corresponding to level 2 of the categorical variable? 1. E(y) = Bo + B121 2. E(y) = Bo + 3272 3. E(y) = Bo + BIT1 + B2 4. E(y) = Bo + B121 + B272 - Select your answer - d. Interpret the parameters in your regression equation. 82 = - Select your answer - B1 is the change in E(y) for a 1 unit change in - Select your answer - | holding the categorical variable constant