Estimation of transition probabilities for the
	illness-death model and or the three-state progressive model.

Provide data generation and estimation tools for the truncated positive normal (tpn)
             model discussed in Gomez, Olmos, Varela and Bolfarine (2018) 
             <doi:10.1007/s11766-018-3354-x>, the slash tpn distribution discussed in Gomez, 
             Gallardo and Santoro (2021) <doi:10.3390/sym13112164>, the bimodal tpn distribution 
             discussed in Gomez et al. (2022) <doi:10.3390/sym14040665>, the flexible tpn model
	     <doi:10.3390/math11214431> and the unit tpn distribution <doi:10.1016/j.chemolab.2025.105322>.

Regression models for temporal process responses with
        time-varying coefficient.

Performs turning point and inflection point tests for 
    U-shaped and inverse U-shaped relationships in regression models.
    Implements the Sasabuchi (1980) test as extended by Lind and Mehlum (2010)
    with support for quadratic, cubic, log-quadratic, and inverse functional
    forms. Features include delta-method standard errors, Fieller confidence
    intervals, Simonsohn (2018) two-lines test, and parametric bootstrap.
    Designed for post-estimation analysis of linear models, panel models,
    and quantile regression.
    References: Lind and Mehlum (2010) <doi:10.1111/j.1468-0084.2009.00569.x>;
    Sasabuchi (1980); Fieller (1954) <doi:10.1111/j.2517-6161.1954.tb00159.x>.

Density, distribution function, the quantile function, 
    random generation function, and maximum likelihood estimation.

The two-parameter Xgamma and Poisson Xgamma distributions are analyzed, covering standard distribution and regression functions, maximum likelihood estimation, quantile functions, probability density and mass functions, cumulative distribution functions, and random number generation. References include: "Sen, S., Chandra, N. and Maiti, S. S. (2018). On properties and applications of a two-parameter XGamma distribution. Journal of Statistical Theory and Applications, 17(4): 674--685. <doi:10.2991/jsta.2018.17.4.9>." "Wani, M. A., Ahmad, P. B., Para, B. A. and Elah, N. (2023). A new regression model for count data with applications to health care data. International Journal of Data Science and Analytics. <doi:10.1007/s41060-023-00453-1>."