You want to use dichotomous variables to estimate a model. Assume that you have 100 observations and the dichotomous variable takes the value zero in the first 50 and one in the second 50. The model is as follows:

Yt = Alpha + BXt + Et

You suspect that there is a structural change from the 51 observation in the slope of the basic model.

Which of the following models should you estimate to investigate?

a) Y. = a1 + D. X+ + BIX + & b) Y. = at a2D, + BIX, +. c) Y. = a, + BIX, + B2X.D. + . d) Y = a, + a2D, + BIX.D. +