The Probit Model:

Setting F(x_iβ)  to  be  the  normal  distribution,  in  the  regression approach (used  in many analyses), gives rise to the probit model. Similarly, assuming that E,  follows a standard normal  distribution  conditional on x_i,  in  the  latent regression approach, will  also give rise  to the probit model. The normal density is symmetric about its mean and therefore the expressions written as

The function φ(.)  is a commonly used notation  for the standard normal probability density function.