Statistics Calculators
Hypothesis tests, confidence intervals, regression, correlation, and descriptive statistics — each with formulas and interpretation.
Weighted Mean Calculator
Enter your values and their weights to get the weighted mean instantly, along with the sum of…
Anderson-Darling Test Calculator
A², adjusted A*², p-value, the 15%-1% critical value table, and a Kolmogorov-Smirnov comparison…
ANOVA Calculator
Paste one group per line and read the F statistic, degrees of freedom, p-value, eta squared…
Outlier Detection Calculator
Identify the extreme observations in your data with the Tukey 1.5·IQR rule, the z-score, or the…
Independent Samples t-Test Calculator
Pooled and Welch t values, Levene's test, p-value, confidence interval, Cohen d, Hedges g, and…
Bartlett's Test Calculator
Χ², the correction factor C, df, p, critical χ², pooled variance, a normality check, and a…
Bayes' Theorem Calculator
Turn a prior probability, sensitivity, and specificity into a posterior probability: positive…
Expected Value Calculator
E(X) = Σxᵢ·pᵢ together with variance, standard deviation, a working table, and probability…
Coefficient of Determination (R²) Calculator
Compute R², adjusted R², the standard error of the estimate, the SST/SSR/SSE decomposition, and…
Bernoulli Distribution Calculator
Compute P(X=1), P(X=0), the mean, variance, skewness, and kurtosis of a Bernoulli trial, and…
Descriptive Statistics Calculator
Paste a data set to get the mean, median, mode, standard deviation, quartiles, skewness…
Binomial Distribution Calculator
Compute P(X = k), P(X ≤ k), P(X ≥ k), and range probabilities from n and p, together with the…
Crosstab Calculator
Build a contingency table with observed and expected counts, row and column percentages, the…
Skewness and Kurtosis Calculator
Compute skewness (g1) and kurtosis (g2) with standard errors and z-ratios, plus the…
Draw Probability Calculator
With K targets among N objects and n draws, get the chance of exactly k and at least k, plus…
Interquartile Range (IQR) Calculator
Compute Q1, the median, Q3, and the interquartile range, then read the Tukey outlier fences…
Cohen's d Calculator
Get Cohen's d, Hedges g, Glass delta, a confidence interval, and a plain-English effect size…
Cohen's Kappa Calculator
Get observed and chance agreement, SE, z, p, a confidence interval, kappa_max, and the…
Multiple Regression Calculator
Coefficient table with b, SE, t, p, and confidence intervals, plus R², adjusted R², the F test…
Cramér's V Calculator
Turn a chi-square value, sample size, and table size into Cramér's V, phi, and Cohen's w, with…
Cronbach's Alpha Calculator
Paste your respondent-by-item score matrix and get Cronbach's alpha, corrected item-total…
Coefficient of Variation Calculator
Compute the coefficient of variation with CV = s / |x̄|, compare two series measured in…
Uniform Distribution Calculator
Density, P(x₁ < X < x₂), tail probabilities, mean, variance, quartiles, and quantiles with a…
Paired Samples t-Test Calculator
Mean difference, t, df, p-value, the confidence interval for the difference, Cohen's d, a…
Eta Squared Calculator
Compute eta squared, partial eta squared, omega squared, and Cohen f from ANOVA sums of squares…
Effect Size Conversion Calculator
Convert between Cohen d, correlation r, odds ratio, Cohen f, and eta squared in both…
F Distribution Calculator
Find the upper-tail p-value for any F, df₁, and df₂, or the critical F for a given α, with the…
Fisher's Exact Test Calculator
Two-tailed and one-tailed exact p-values, the odds ratio with a confidence interval, and a…
Frequency Table Calculator
Paste raw data and get the full frequency table — class intervals, frequency, relative…
Friedman Test Calculator
The Friedman Q statistic, df, p-value, critical chi-square, Kendall's W, rank sums, and the…
Geometric Distribution Calculator
Compute P(X = k), P(X ≤ k), and P(X > k) = (1−p)^k for the trials needed until the first…
Geometric Mean Calculator
The right average for growth rates and compound returns, with the gap to the arithmetic mean.
Relative Risk Calculator
Compute the relative risk (RR), absolute risk difference, NNT/NNH, and confidence intervals…
Stem-and-Leaf Plot Calculator
Turn your data into a stem-and-leaf plot with an automatic stem unit, per-row frequencies and…
Grouped Data Mean Calculator
Enter class intervals and frequencies to get the grouped mean, variance, standard deviation…
Confidence Interval Calculator
Compute the 90%, 95%, or 99% confidence interval for a mean or a proportion: margin of error…
Harmonic Mean Calculator
The correct average for speeds, unit costs, and ratios, with optional weights and a comparison…
Hypergeometric Distribution Calculator
Compute P(X = k), cumulative and range probabilities for sampling without replacement, with the…
Two-Group Sample Size Calculator
Find the sample size per group for comparing two independent means from Cohen's d, target…
Two-Proportion Confidence Interval Calculator
Compute Wald and Newcombe hybrid confidence intervals for the difference between two…
Two-Proportion Z-Test Calculator
Z, p-value, critical value, Newcombe confidence interval, Cohen h, and the contingency table.
Two-Mean Difference Confidence Interval Calculator
Build the confidence interval for the difference between two independent means (x̄₁ − x̄₂) with…
Two-Way ANOVA Calculator
SS, df, MS, F, p, and partial eta squared for both main effects and the interaction, plus cell…
Sign Test Calculator
Compare paired measurements using only the signs of the differences: plus, minus, and tie…
Statistical Power Calculator
Compute statistical power (1 − β) and the Type II error rate from sample size, effect size, and…
Square Root and Inverse Transform Calculator
Compare square root, cube root, and inverse (1/x) transformations on the Tukey ladder: skewness…
Kendall Tau-b Correlation Calculator
Concordant and discordant pair counts, the tie correction, the S statistic, z and p, a…
Chi-Square Test Calculator
Paste your contingency table frequencies and get the χ² statistic, degrees of freedom, p-value…
Chi-Square Goodness of Fit Calculator
Test whether observed frequencies match an expected distribution: chi-square, degrees of…
Partial Correlation Calculator
Zero-order correlations, the t test, the p-value, and a Fisher z confidence interval.
Kolmogorov-Smirnov Test Calculator
D, D⁺, D⁻, the critical D, and the classical and Lilliefors p-values side by side, with a CDF…
Correlation Coefficient Calculator
Paste your X and Y data and get Pearson r, Spearman rho, r², the t statistic, the p-value, and…
Conditional Probability Calculator
Get the reverse conditional, the union, lift, an independence check, and a step-by-step…
Critical Value Calculator
Get critical values for the z, t, chi-square, and F distributions without a printed table…
Kruskal-Wallis H Test Calculator
H statistic, tie correction, df, p-value, critical chi-square, eta and epsilon squared, and a…
Levene's Test Calculator
W, df, p, critical F, group variances with confidence intervals, and a box plot.
Log Transformation Calculator
Apply an ln, log₁₀, or log(x+1) transformation to your data, compare skewness and kurtosis…
Mann-Whitney U Test Calculator
U1, U2, rank sums, z, p, the r effect size, a median-difference confidence interval, a rank…
Median and Mode Calculator
Paste your data and get the median, the mode, the mean, the quartiles (Q1 and Q3), the…
Min-Max Normalization Calculator
Transformed value table, outlier impact, z-score comparison, and before-and-after histograms.
Minimum Detectable Effect (MDE) Calculator
Find the smallest effect size your study can detect from its sample size, power, and alpha —…
Mode Calculator
Mode, mode frequency, unimodal or bimodal type, a full frequency table, bar chart, and…
Negative Binomial Distribution Calculator
Compute P(X = k), cumulative and interval probabilities for the failures before the rth…
Normal Distribution Calculator
Enter the mean and standard deviation to get P(X < x), P(X > x), and P(a < X < b), the z…
Odds Ratio Calculator
Ln(OR), standard error, confidence interval, Wald z and p, the Haldane-Anscombe correction, and…
Probability to Odds and Logit Calculator
Convert between probability, odds, and logit in both directions, and see how a logistic…
Confidence Interval for a Proportion Calculator
Compute a confidence interval for a percentage with the Wilson score and Wald methods side by…
One-Sample Proportion Test Calculator
Expected-count check, corrected and uncorrected z, p-value, Wilson confidence interval, and a…
Sample Size Calculator
Find the minimum sample size your survey needs using Cochran's formula and the finite…
Sample Size for a Mean Calculator
Find the sample size needed to estimate a mean at a chosen margin of error using n = (z·σ/E)²…
Confidence Interval for a Mean Calculator
The t or z critical value is picked automatically, with margin of error, bounds, width, and a…
Mean Calculator
Paste your numbers and get the arithmetic, geometric, and harmonic mean plus the median, sum…
P-Value Calculator
Turn a z, t, chi-square, or F test statistic into an exact p-value: one- and two-tailed…
Poisson Distribution Calculator
Compute P(X = k), P(X ≤ k), P(X ≥ k), and interval probabilities from the rate λ; see the mean…
Linear Regression Calculator
Paste X and Y and get the regression equation, R², the significance test for the slope, and a…
Regression Prediction Interval Calculator
Get the confidence interval for the mean response and the prediction interval for a single…
Runs Test Calculator
Runs R, n1, n2, expected R, standard deviation, z, p with and without continuity correction…
Shapiro-Wilk Test Calculator
Paste your data and get the Shapiro-Wilk W statistic, p-value, critical W, skewness, kurtosis…
Spearman Rank Correlation Calculator
Compute Spearman rho with a rank transformation table, tie correction, a t-test p-value, a…
Standard Score Conversion Calculator
Convert in both directions between z-scores, T scores, percentile ranks, stanines, sten, IQ…
Standard Deviation Calculator
Paste your data and get the sample and population standard deviation, variance, mean, median…
Z-Score Standardization Calculator
Every observation's z value and T score in a table, with a step-by-step check that the mean is…
T-Test Calculator
Run a one-sample or independent samples t-test from summary statistics: t value, degrees of…
Diagnostic Test Calculator
Compute sensitivity, specificity, PPV, NPV, accuracy, F1, LR+, LR−, diagnostic odds ratio, and…
One-Sample t-Test Calculator
T, degrees of freedom, p-value, critical t, the confidence interval for the difference, Cohen…
Repeated Measures ANOVA Calculator
Sum-of-squares breakdown, F, df, p, partial eta squared, sphericity corrections, and a full…
Law of Total Probability Calculator
Compute P(B) = ΣP(B|Aᵢ)·P(Aᵢ) with the law of total probability: see the contribution of every…
Exponential Distribution Calculator
Compute P(X≤x), P(X>x), and interval probabilities from the rate λ or the mean waiting time…
Variance Confidence Interval Calculator
Build the chi-square based asymmetric confidence interval for σ² and σ: critical values…
Variance Calculator
Paste your data and get the sample or population variance, standard deviation, and mean, with a…
Variance Ratio F Test Calculator
F, df, critical F, p-value, a confidence interval for the ratio, and a Levene comparison.
Wilcoxon Signed-Rank Test Calculator
W⁺, W⁻, T, z, p, the r effect size, a confidence interval for the median change, and the…
Percentile Calculator
Find the value at any percentile of your data, or work backwards and see where a single score…
Percentile Rank Calculator
Compute the percentile rank of a value under three definitions, work backwards from a…
Z-Score Calculator
Turn a raw score into a z-score from the mean and standard deviation, and read the percentile…
Z-Test Calculator
Z statistic, p-value, critical z, confidence intervals, Cohen's d, and a shaded normal curve of…