Statistics Calculators
Enter a data set to get its mean, median, standard deviation or percentiles, or run a z-score, t statistic, confidence interval or chi-square test. The formula behind each result is on its page.
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17 toolsChi-Square Goodness of Fit Calculator
Compare observed and expected counts with a chi-square statistic, tail p-value, and count screen.
Open calculatorCoefficient of Variation Calculator
Compare relative spread from supplied summaries or two raw datasets.
Open calculatorConfidence Interval Calculator
Estimate a mean with a known-spread z or sample-spread t interval, or a Wilson proportion interval.
Open calculatorCorrelation Calculator
Compare Pearson value correlation and Spearman rank correlation for the same paired observations.
Open calculatorInterquartile Range Calculator
Find quartiles, IQR, and outlier fences using interpolation or medians of halves.
Open calculatorLinear Regression Calculator
Fit a least-squares line, predict an outcome, and inspect residual error and the fitted equation.
Open calculatorMean Absolute Deviation Calculator
Calculate average absolute distance from the mean using a list or value frequencies.
Open calculatorMean, Median & Mode Calculator
Find mean, median, modes, and a frequency breakdown from individual numbers or counts.
Open calculatorNormal Distribution Calculator
Calculate normal-model probabilities or find the cutoff for a chosen percentile.
Open calculatorPercentile Calculator
Find an interpolated or nearest-rank percentile from observations or value frequencies.
Open calculatorProbability Calculator
Calculate single-event, binomial and two-event probabilities with complements and working.
Open calculatorSample Size Calculator
Plan a sample size or estimate the margin attainable with an available sample.
Open calculatorStandard Deviation Calculator
Calculate sample or population spread from a number list or value frequencies.
Open calculatorStandard Error Calculator
Calculate standard error from a sample or summaries and plan a target standard error.
Open calculatorT Statistic Calculator
Calculate a one-sample t statistic and p-value from summaries or raw sample observations.
Open calculatorWeighted Average Calculator
Calculate a weighted mean and solve the next value needed to reach a target average.
Open calculatorZ-Score Calculator
Convert an observation, z-score, or normal percentile into matching scores and tail areas.
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