Resources
Distribution tables and reference tools for classroom and research work.
Distribution tables and reference tools for classroom and research work.
Stats Calculator Online
Keep exploring free calculators, formulas, and tables
Best practice
Check assumptions before you trust p
Independence, normality (or large n), and equal variances matter for classic t/ANOVA. Use Welch or rank tests when they fail.
Two-sample t-test →Plan ahead
Power before you collect data
Fix the smallest meaningful effect and α, then compute sample size. Inflate n for dropout when recruiting humans.
Sample size calculator →Everyday math
Percent change ≠ percent of
Percent of is part÷whole. Percent change uses the starting value in the denominator—and +50% then −50% does not return to start.
Percentage calculators →High-traffic tools on Stats Calculator Online — jump in with sample data
Deep links to popular tools, topic hubs, and critical-value tables.
Popular calculators
Topic hubs