Example 75

The PROBIT Procedure.

Example 75.3 Logistic Regression. In this example, a series of people are asked whether or not they would subscribe to a new newspaper. For each person, the variables sex (Female, Male), age , and subs (1=yes,0=no) are recorded. The PROBIT procedure is used to fit a logistic regression model to the probability of a positive response (subscribing) as a function of the variables sex and age . Specifically, the probability of subscribing is modeled as.

where F is the cumulative logistic distribution function. By default, the PROBIT procedure models the probability of the lower response level for binary data. One way to model is to format the response variable so that the formatted value corresponding to is the lower level. The following statements format the values of subs as 1 = ’accept’ and 0 = ’reject’, so that PROBIT models . They produce Output 75.3.1. Output 75.3.1: Logistic Regression of Subscription Status.