15.7 Practice Questions Exercise 15.32 Algo (Categorical Independent Variables) 4 Quesum'l 2 on Check My Work Consider a regression study involving a dependent variable y, a quantitative independent variable 32, and a categorical independent variable with two levels [level 1 and level 2]. 3. Write a multiple regression equation relating z; and the (ategorical variable to y 1. E(y) = Bu +5121 2. EU!) : 60 +522: 3- EU?) = 30 +31$1 +321 4- Ell!) = 30 +3131 +323! iWI Enter the values of dummy variable xi that are used to indicate the two levels of the qualitative variable. If your answer is zero, enter \"0". fl Level 1 Level 2 b. What is the expected value ofy corresponding to level 1 of the categorical variable? 1. EU!) : u +5121 2. EU!) : 60 +522: 3- EU?) = 30 +31$1 +321 4- Em) : 30 +3131 +3222 1:. What is the expected value of'y (orresponding to level 2 of the categorical variable? 1- E(l'1)= 30 +3131 2- Em) : 150 +322: 3- EW) = 3n +3131 +31 4- EU?) = 30 +31 + 323:! i ' I d. Interpret the parameters in your regression equation. eled you answe .131 :i 7 Salad your answer , vi .32 is the change in Em) for a 1 unit change in Select your answer , v i holding the categorical variable constant