Statistics calculators
19 free statistics tools, each with the formula and step-by-step working.
- Average CalculatorMean, median, mode and range from a list.
- Binomial Distribution CalculatorProbability of k successes in n trials.
- Chi Square CalculatorGoodness of fit test statistic.
- Confidence Interval CalculatorMargin of error and interval around a sample mean.
- Correlation Coefficient CalculatorPearson r for two data sets.
- Empirical Rule CalculatorTurn a mean and standard deviation into the 68%, 95% and 99.7% intervals.
- Interquartile Range CalculatorIQR, quartiles and outlier fences.
- Linear Regression CalculatorBest fit line for paired data.
- Margin of Error CalculatorThe ± figure behind any poll or survey result.
- Normal Distribution CalculatorProbabilities under the bell curve.
- Poisson Distribution CalculatorProbability of k events in an interval.
- Probability CalculatorCombined probability of independent events.
- Quartile CalculatorQ1, median, Q3 and five number summary.
- Sample Size CalculatorHow many responses you need for a reliable survey.
- Standard Deviation CalculatorSample and population spread, variance and standard error.
- T Test CalculatorOne-sample and two-sample t statistics.
- Variance CalculatorSample and population variance.
- Weighted Average CalculatorAverages where some values count more than others.
- Z-Score CalculatorStandard score, percentile and tail probabilities.
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