Parameter estimation for zero-inflated discrete Weibull (ZIDW) regression models, the univariate setting, distribution functions, functions to generate randomized quantile residuals a pseudo R2, and plotting of rootograms. For more details, see Kalktawi (2017) < https://bura.brunel.ac.uk/handle/2438/14476>, Taconeli and Rodrigues de Lara (2022)