BioStat Lab

BioStat Lab is a precise, offline statistical power and sample size calculator designed for biomedical researchers, clinicians, and students. CALCULATORS INCLUDED t-Test — Independent & Paired Calculate the required sample size for independent-samples or paired t-tests. Enter mean difference, standard deviation, significance level (α), and desired power (1−β). ANOVA — One-Way Determine per-group and total sample size for a one-way ANOVA across 2–20 groups. Uses Bonferroni-adjusted alpha for multiple-comparison control. Proportions — Two-Proportion z-Test Compare two event rates or response proportions. Displays absolute difference and risk ratio alongside the required sample size per group. Correlation — Pearson r Sample size for testing whether a Pearson correlation is significantly different from zero. Uses Fisher z-transformation for accuracy. Includes Cohen's effect-size classification. Survival — Log-Rank Test Event-driven sample size for survival studies using Freedman's formula. Enter hazard ratio, expected event rate, α, and power to get required events and total subjects. DESIGN PHILOSOPHY Dark space-inspired interface — deep indigo background, violet accent readouts, monospaced numeric displays — optimized for focused scientific work. PRIVACY No account required. No data collected. All calculations happen on-device.