We consider concepts and models that are useful for measuring how strongly the distribution of a positive response Y is concentrated near a value with a focus on how concentration varies as a function of covariates. We combine ideas from statistics, economics and reliability theory. Lorenz...

We consider concepts and models for measuring inequality in the distribution of resources with a focus on how inequality varies as a function of covariates. Lorenz introduced a device for measuring inequality in the distribution of income that indicates how much the incomes below the u$^{th}$...

The problem of classifying a categorical response Y is considered in a nonparametric framework. The distribution of Y depends on a vector of predictors X, where the coordinates Xj of X may be continuous, discrete, or categorical. An algorithm is constructed to select the variables to be used for...