8 Chapter 9 extends the bivariate logit and probit models to multi-category nominal scale variables, where the regress and has more than two nominal values. For example, consider the means of transportation to work. Suppose we have three choices: private car, public bus, or train. How do we decide among these choices? Can we still use OLS? As we will show in this chapter, such problems require nonlinear estimation techniques. Multinomial conditional logit or multinomial probit models discussed in this chapter show how multi-category nominal scale variables can be modeled.