Instrumental Variables, Endogeneity, Regression, Linear Regression, Python.
β*_2 is the effect of Legacy, and not Attended_Ivy_League on Lifetime_Earnings. But we have seen that β_2 cannot be estimated reliably anyway. So we must accept β*_2 as the representative of β_2. Incidentally, estimation software will report β*_2 as the coefficient of the original endogenous