stagelife: Random Number Generation and Inferences for Two-Stage Life-Testing Data

Provides random number generation, estimation, and hypothesis testing for two-stage life-testing experiments in which units begin on a baseline stress and, at a fixed or random change point, some or all surviving units move to an elevated stress ("stage life testing"), following the cumulative-exposure model of Laumen and Cramer (2019), "Stage life testing", <doi:10.1002/nav.21874>. Twelve baseline lifetime distributions are supplied (Weibull, Power Lindley, Exponentiated Lindley, Exponentiated Exponential, Marshall-Olkin Exponential, Lomax, Exponentiated Teissier, Log-Logistic, Chen, Log-normal, Gamma, and Power Muth/Power Teissier) together with three parameter-sharing cases (common, shape1, shape11). The package implements data simulation under both the fixed-proportion (typeP) and fixed-count (typeM) rules and the simple-step-stress special case, maximum likelihood estimation using a hybrid Nelder-Mead and BFGS optimisation routine, asymptotic (Wald) and non-parametric/parametric bootstrap confidence intervals (including log-scale variants that guarantee a positive interval), a stage-1-observation planning probability, Kolmogorov-Smirnov goodness-of-fit testing with a parametric-bootstrap correction for estimated parameters, likelihood-ratio and information criteria for nested/non-nested model comparison, and diagnostic plots comparing fitted and empirical distributions, including the cumulative distribution function (CDF), survival function, probability-probability (P-P), and quantile-quantile (Q-Q) plots.

Version: 0.1.0
Depends: R (≥ 4.1.0)
Imports: compiler, ggplot2, graphics, lamW, parallel, stats
Suggests: knitr, rmarkdown, testthat (≥ 3.0.0)
Published: 2026-11-03
DOI: 10.32614/CRAN.package.stagelife (may not be active yet)
Author: Vikas Kumar Sharma [aut, cre]
Maintainer: Vikas Kumar Sharma <vksharma at bhu.ac.in>
BugReports: https://github.com/vksharma-bhu/stagelife/issues
License: MIT + file LICENSE
URL: https://github.com/vksharma-bhu/stagelife
NeedsCompilation: no
Citation: stagelife citation info
Materials: README, NEWS
CRAN checks: stagelife results

Documentation:

Reference manual: stagelife.html , stagelife.pdf
Vignettes: Introduction to stagelife: Two-Stage Life Testing (source, R code)

Downloads:

Package source: stagelife_0.1.0.tar.gz
Windows binaries: r-devel: not available, r-release: stagelife_0.1.0.zip, r-oldrel: stagelife_0.1.0.zip
macOS binaries: r-release (arm64): stagelife_0.1.0.tgz, r-oldrel (arm64): stagelife_0.1.0.tgz, r-release (x86_64): stagelife_0.1.0.tgz, r-oldrel (x86_64): stagelife_0.1.0.tgz

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