Assessment Tools for Regression Models with Discrete and Semicontinuous Outcomes

Provides assessment tools for regression models with discrete and semicontinuous outcomes. The implemented methods are described in Yang (2021) , Yang (2024) , Yang (2024) , and Yang (2026) . It calculates double probability integral transform (DPIT) residuals and constructs QQ plots, ordered curves, quasi-empirical residual distribution functions, and formal goodness-of-fit tests.