Statistics tools and calculators
A set of free calculators for the statistics a dissertation or thesis actually needs: planning the sample size, choosing the right test, reporting results in APA style, and checking reliability and effect size. Each one shows the formula behind the number, so it is a working tool, not a black box.
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Sample size and power calculatorSolve for the sample size you need, the power you have, or the smallest effect you could detect, across seven tests.Open tool Statistical test selectorAnswer a few questions about your design and get the statistical test that fits, with the reasoning shown.Open tool T-test calculatorRun a one-sample, paired, or independent-samples t-test from raw data or summary figures, with the exact p-value.Open tool P-value calculatorConvert a t, z, F, or chi-square statistic into an exact p-value from the right distribution.Open tool Confidence interval calculatorBuild a confidence interval for a mean, a proportion, or a correlation from your data or summary figures.Open tool Chi-square test calculatorTest independence in a contingency table for the chi-square statistic, expected counts, and Cramer's V.Open tool Correlation coefficient calculatorGet Pearson's r or Spearman's rho from two columns, with the significance test and r-squared.Open tool One-way ANOVA calculatorCompare three or more group means for the F statistic, p-value, and eta-squared, with a full ANOVA table.Open tool Linear regression calculatorFit a simple linear regression from two columns for the slope, intercept, r-squared, and significance test.Open tool
More calculators
APA results formatterTurn a t, F, chi-square, or correlation result into a correctly formatted APA sentence.Open tool Cronbach's alpha calculatorPaste your item-by-respondent scores and get Cronbach's alpha with per-item reliability statistics.Open tool Effect size calculatorCompute Cohen's d, Hedges' g, eta-squared, and convert between odds ratios and risk ratios.Open tool Descriptive statistics calculatorPaste a column of data for the mean, median, SD, variance, skewness, kurtosis, and a 95% confidence interval.Open tool Z-score calculatorConvert a raw value to a z-score and a percentile, or recover the value behind a z-score.Open tool
Working through the analysis itself? The statistics guides explain the methods behind these tools, our hands-on SPSS support walks you through the software, and full analysis of your results chapter is there when you would rather hand it over.