90 likes | 192 Views
Lecture 25 (Dec.4). In the last lecture, we covered Log-log specification Interaction term This lecture introduces you to Interaction term. Interactions Between Independent Variables (SW Section 8.3). (a) Interactions between two binary variables. When does this term become positive?.
E N D
Lecture 25 (Dec.4) In the last lecture, we covered • Log-log specification • Interaction term This lecture introduces you to • Interaction term
(a) Interactions between two binary variables When does this term become positive?
Interpreting the coefficients What is the marginal effect of D1: 0→1 if D2=0? What is the marginal effect of D1: 0→1 if D2=1?
Interpreting the coefficients What is the marginal effect of D1: 0→1 if D2=0? What is the marginal effect of D1: 0→1 if D2=1?
Interpreting the coefficients What does β3 represent?
Example: TestScore, STR, English learners • What is the “Effect” of HiSTR when HiEL = 0 ? • What is the “Effect” of HiSTR when HiEL = 1 ? • What do you conclude from the above result?
(b) Interactions between continuous and binary variables When does this term become positive?