Logit, Probit and Tobit: Models for Categorical and Limited ...

The Logit and Probit Models
– In the logit model model, we can interpret b as an effect
on the odds. That is, every unit increase in X
results in a multiplicative effect of eb p
on the odds.
Example: If b = 0.25, then e .25 = 1.28. Thus, when X
changes by one unit, p increases by a factor of 1.28, or
changes by 28%.
- In the probit model, use the Z-score terminology.
FFor every unit it increase i in i X, X the th Z Z-score ( (or th the
Probit of “success”) increases by b units. [Or, we
can also say that an increase in X changes Z by b
standard deviation units.]
- If you like, you can convert the z-score to probabilities
y ,y p
using the normal table.