Statistics calculators that show you how.
Statoma helps you run common statistics calculations and read the result in context: what the method asks, what the numbers mean, and which assumptions deserve attention before you report the answer.
How Statoma Works
Each Statoma calculator starts with a focused statistical question. Instead of asking you to choose from a long menu of unrelated options, the page explains what the calculator is for, which inputs matter, how the formula is built, and how to interpret the result without overstating it. The calculation happens in your browser, and the educational text stays close to the tool so the reasoning does not get separated from the number.
The first release covers the workflows students and applied researchers most often need at the beginning of an analysis: tests for means, p-values from common test statistics, confidence intervals, sample size planning, and chi-square tests for categorical counts. Every calculator page includes a worked example and common mistakes because the same arithmetic can be misleading when the design or assumptions do not fit.
What The Calculators Cover
Use the t-test calculator for one-sample, paired, independent, and Welch comparisons when your question is about means. Use the p-value calculator for z, t, chi-square, and F statistics when a test statistic has already been computed and you need the matching tail probability.
When the goal is estimation rather than a yes-or-no test, the confidence interval calculator for means, proportions, and differences shows the estimate, standard error, margin of error, and bounds. When the study is still being planned, the sample size calculator for precision and power connects assumptions to the number of analyzable observations needed. For categorical counts, the chi-square calculator for goodness of fit and independence compares observed counts with expected counts.
How To Choose A Calculator
Start with the form of the data and the claim you want to make. If the outcome is numeric and the claim is about an average, a t-test or confidence interval may fit. If the outcome is categorical and the data are counts in categories, a chi-square workflow may fit. If the question is about planning, sample size belongs before data collection, not after a result looks inconvenient.
If you are unsure, open the full Statoma calculator index. It explains each tool by the statistical question it answers, so the first decision is the method rather than a formula hunt.