The function used was the

probit function rather than the logit function, although both functions produce quite similar results.

5), the

probit function Y allows a useful and fast correlation of probit values to a dose (in this case represented by the PGA value) by means of the two constants k1 and k2.

The specification is a Probit function, where the dependent variable is a binary choice proxying for the propensity to migrate from region i to region j: in particular, M=1 if there was a migration flow at any time after 1992 from district i to district j, and 0 otherwise; [[?

Employing aggregate data, the migration probit function confirmed the role of economic variables in the migration decision.

As established in the previous section, the key to estimating a consistent ATE of FTAs on trade is, first, finding a probit function that predicts FTAs and, second, finding variables for z (instruments) that are uncorrelated with the gravity equation error term.

We consider two possibilities, a probit function and a linear probability model.

Following Baier and Bergstrand (2004), we estimate a probit function of P(FTA) where, motivated by the theoretical model in that paper, economic determinants of the likelihood of a country pair having an FTA include the standard gravity equation variables in q and a set of instruments z: remoteness of the country pair from the ROW (REMOTE), difference in their capital-labor ratios (DKL), and the difference in the pair's K-L ratio from that of the ROW (DROWKL).

The probit function is static by design, because it seeks to measure the unchanging portion of addictive propensity, so it can not follow changing cigarette prices.

Information as to marital stability (Divorced) is also included in the probit function to control for characteristics such as a high discount rate or chronically high stress level that may be correlated with marriage breakup.

These predicted ERs are very similar to the sample ERs in Table 4, but they are not identical since the probit function need not pass through the point of sample means.

The largest coefficient change for married mothers in Table 6 was the increase in the intercept of the probit function.

Present study analyses the determinants of primary school enrolment in Pakistan by estimating separate

probit functions for the three headship scenarios.