25 calculators
Statistics & Probability
Describe data, test it, and count the chances.
Within ±1σ68.27%
σStandard deviationHow spread out your numbers are around their mean, for a sample or a whole population.Top 100 · #59Open →s²VarianceThe average squared distance of your numbers from their mean.Top 100 · #60Open →zZ-scoreHow many standard deviations a value sits above or below the mean, and the share of a normal distribution below it.Top 100 · #66Open →PPercentileThe value below which a given percentage of your data falls, and where any value ranks.Top 100 · #67Open →QQuartilesThe three cut points that split your sorted data into four equal parts.StatsOpen →x̃MedianThe middle value of your data once it is sorted.Top 100 · #68Open →MoModeThe value or values that appear most often in your data.Top 100 · #69Open →PProbabilityThe chances of both, either, or neither of two independent events happening.Top 100 · #61Open →nCrCombinationsHow many ways to choose r items from n when the order does not matter, exactly.Top 100 · #62Open →nPrPermutationsHow many ordered arrangements of r items can be taken from n, exactly.Top 100 · #63Open →CIConfidence intervalThe range that likely holds the true mean, from a sample mean, standard deviation and size.Top 100 · #64Open →nSample sizeHow many responses a survey needs for a chosen confidence level and margin of error.Top 100 · #65Open →pP-valueThe p-value for a z or t test statistic, one- or two-tailed.StatsOpen →rCorrelationPearson's r: how closely two sets of paired numbers follow a straight line.StatsOpen →ŷLinear regressionThe least-squares line through paired data, its fit, and a prediction.Top 100 · #71Open →NNormal distributionThe probability of a value below, above or between points on a normal curve.StatsOpen →BBinomialThe chance of exactly, at most or at least k successes in n independent tries.StatsOpen →x̄wWeighted averageThe average when some values count for more than others, such as graded coursework.Top 100 · #70Open →GGeometric meanThe typical value of numbers that multiply together, such as growth rates.StatsOpen →HHarmonic meanThe right average for rates, such as speeds over equal distances.StatsOpen →IQRInterquartile rangeThe spread of the middle half of your data, and the fences that flag outliers.StatsOpen →5#Five-number summaryMinimum, first quartile, median, third quartile and maximum: the outline of a box plot.StatsOpen →CVCoeff. of variationThe standard deviation as a percentage of the mean, to compare spread across scales.StatsOpen →±Margin of errorThe plus-or-minus on a survey result, from the sample size and the share who answered.StatsOpen →RNGRandom numbersRandom whole or decimal numbers in any range, with or without repeats.StatsOpen →
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