Sequential Probability Ratio Tests Toolbox R package sprtt version 0.3.1 A toolbox for Sequential Probability Ratio Tests (SPRT) based on Wald (1945) <doi:10.2134/agronj1947.00021962003900070011x>. SPRTs are applied during the sampling process, ideally after each observation, and at every stage return a decision to either continue sampling or terminate and accept one of the specified hypotheses. The `seq_ttest()` function performs one-sample, two-sample, and paired t-tests for one- and two-sided hypotheses (Schnuerch & Erdfelder (2019) <doi:10.1037/met0000234>). The `seq_anova()` function performs a sequential one-way fixed effects ANOVA (Steinhilber et al. (2024) <doi:10.1037/met0000677>). The `plan_sample_size()` function helps plan sequential studies by simulating required sample sizes across a range of effect sizes. For more information, see the vignettes browseVignettes(package = "sprtt") or the package website <https://meikesteinhilber.github.io/sprtt/>. Software Depends: R (>= 3.5.0) Imports: rappdirs, methods, stats, dplyr, MBESS, purrr, glue, ggplot2, lifecycle, knitr, rmarkdown, gt, ggtext, scales, piggyback Suggests: testthat (>= 3.0.0), testthis, withr, xml2, effsize, effectsize, vdiffr, diffviewer Meike Snijder-Steinhilber <Meike.Steinhilber@aol.com> Comprehensive R Archive Network (CRAN) Meike Snijder-Steinhilber [aut, cre] (ORCID: <https://orcid.org/0000-0002-7144-2100>), Martin Schnuerch [aut, ths] (ORCID: <https://orcid.org/0000-0001-6531-2265>), Anna-Lena Schubert [aut, ths] (ORCID: <https://orcid.org/0000-0001-7248-0662>) AGPL (>= 3) 2026-05-06 application/tgz https://CRAN.R-project.org/package=sprtt doi:10.32614/CRAN.package.sprtt en-US