Hint(s) Check My Work Consider a regression study involving a dependent variable y, a quantitative independent variable 2:1, and a categorical independent variable with two levels (level 1 and level 2). a. Write a multiple regression equation relating 3:1 and the categorical variable to y. - ECU) = X30 + [3131 - 171(9) = #30 + 32562 - 13(31) = 50 + 51171 + 132 - 137(9) = n + ['31-'51 + [321:2 Enter the values of dummy variable 22 that are used to indicate the two levels of the qualitative variable. If your answer is zero, hUNl-l- enter \"0". Level 1 Level 2 b. What is the expected value ofy corresponding to level 1 of the categorical variable? - ECU) = u + [31% - 171(9) = n + 32562 - 13(31) = 50 + 51171 + 132 - 137(9) = n + ['31-'51 + [321:2 c. What is the expected value of y corresponding to level 2 of the categorical variable? hUNl-l- - ECU) = X30 + [3M1 - 19(31): 50 + 32-192 - 13(9) = 50 + 51931 + 52 - ECU) = u + 51-191 + [32502 d. Interpret the parameters in your regression equation. a = 51 is the change in E(y) for a 1 unit change in holding the categorical variable constant. uhthI-l