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Core descriptive statistics that summarize a data set's center and spread. These are the first calculations in any statistics…
Tools for locating a value within a distribution and describing the distribution's shape. Used for test scores, benchmarking…
Basic probability rules, conditional probability, and expected value. These calculators cover the first half of any probability…
Exact probabilities, cumulative probabilities, and critical values for the distributions used across statistics. Each tool…
Interval estimation and study planning: how precise an estimate is, and how many observations are needed to reach a target…
Significance tests with full test statistics, degrees of freedom, p-values, and decision rules, plus effect size and power. This…
Quantify and model relationships between variables: correlation strength, least-squares lines, model fit, and measures of…
Applied industrial statistics: control chart limits, process capability, defect rates, and measurement system analysis. Follows…
Most used in statistics & probability
- Mean, Median, Mode & Range CalculatorDescriptive statistics (measures of central tendency)Paste a list of numbers and this calculator returns the four summary figures every statistics course starts with: the mean, the…
- Standard Deviation Calculator (Sample & Population)Descriptive statistics (Bessel-corrected sample standard deviation)This calculator returns both standard deviations from the same data: the sample value s , which divides the sum of squared…
- Variance Calculator (Sample & Population)Descriptive statistics (Bessel-corrected sample variance)This calculator returns the sample variance s 2 and the population variance sigma 2 from the same list of numbers, together…
- Weighted Average (Weighted Mean) CalculatorWeighted arithmetic meanEnter your values in one box and their weights in the other and this calculator returns the weighted mean, the total weight…
- Z-Score CalculatorStandard normal distribution (standardisation)A z-score says how many standard deviations a value sits above or below the mean. Enter the raw value, the mean and the…
- Percentile CalculatorSample quantile definitions (Hyndman & Fan, 1996)Enter a data set and a percentile and this calculator returns the value at that point in the sorted data, together with the…
- Quartile & Interquartile Range (IQR) CalculatorTukey's hinges and the 1.5 x IQR outlier rule (Exploratory Data Analysis, 1977)This calculator returns the first quartile, the median, the third quartile and the interquartile range of your data, then…
- Probability Calculator (Single & Two Events)Kolmogorov probability axioms and the addition ruleGive this calculator the probabilities of two events and how they relate, and it returns every derived probability at once: the…
- Bayes' Theorem CalculatorBayes' theorem with the law of total probabilityEnter how common a condition is, how often the test catches it, and how often the test is right when the condition is absent…
- Normal Distribution Probability CalculatorGaussian (normal) distributionEnter a mean, a standard deviation and one or two bounds, and this calculator returns the area under the normal curve: the…
- Z Critical Value Calculator (Inverse Normal)Inverse standard normal (probit) functionThis calculator inverts the normal distribution: instead of turning a cut-off into a probability, it turns a probability into a…
- Binomial Distribution CalculatorBinomial distribution (Bernoulli trials)Enter the number of trials, the probability of success on each one, and the number of successes you care about, and this…