In: Statistics and Probability
consider a simple regression model y1=β1+β2di+ei,with indicator variable di=1 if in individual is in treatment group, and di =0 if in individual is in control group.Proof least squares estimator of β2 satisfies b2=y1-y0, where y1=Σyi/N1 iS the sample mean of the N1 obsevations on y for the treatment group, y0=Σyi/N0, is the sample mean of the N0 observations on y for the control group