Statistics calculators
Mean, standard deviation, p-values and tests. 11 tools
Most popular
A/B Test Significance
Compare conversion rates of two variants and find out whether the difference is statistically significant.
Confidence Interval
Build a confidence interval for a mean from the sample mean, standard deviation and sample size, using z or t.
P-Value
Convert a z-score or t-statistic into a one-tailed or two-tailed p-value and see whether it is significant.
Standard Deviation
Paste a list of numbers to get the sample and population standard deviation, variance and mean, with steps.
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Correlation Coefficient
Paste paired X and Y data to get Pearson’s r, r², the least-squares regression line and a significance test.
Mean, Median, Mode
Find the mean, median, mode and range of a list of numbers, plus the min, max, sum and count.
Normal Distribution
Find probabilities under a normal curve: below a value, above a value, or between two values.
Permutation and Combination
Count the ways to choose r items from n — combinations (nCr), permutations (nPr), with or without repetition.
Probability
For two independent events, find the probability of both, either, exactly one, or neither happening.
Sample Size
Work out how many survey responses you need for a given margin of error and confidence level.
Z-Score
Standardise a value: get its z-score, percentile and the probability above or below it.