Statistics
Descriptive statistics worked out from numbers you enter directly: mean, median, mode, spread, quartiles, percentiles, z scores and simple probability.
Paste or type a list of numbers to get the mean, median, mode and range in one go, or dig into spread with standard deviation, variance or quartiles and the interquartile range. When some values count for more than others, the weighted average takes a weight for each value. Find the value at any percentile of a list, standardise a single score as a z score against a mean and standard deviation you supply, or work out the probability of an event from favourable and total outcomes.
Checking the spread of a set of test scores, finding the quartiles of a small survey sample, or working out how far a test score sits from the class mean.
Conventions and limitations
Standard deviation and variance both offer population and sample modes. Pick sample only when your numbers are a sample drawn from a larger group. Quartiles use the median-of-halves method, with the middle value left out of both halves when the count is odd; other quartile conventions, including a spreadsheet's interpolation-based percentile functions, can give different results on the same data. The Percentile Calculator uses inclusive linear interpolation, so its 25th and 75th percentiles can differ from the quartiles for the same numbers; both are correct for their stated method. The Probability Calculator assumes every outcome is equally likely.
8 tools in this category
- Mean, Median, Mode & RangeFind the mean, median, mode and range of a list of numbers in one step.
- Standard Deviation CalculatorFind the standard deviation of a data set, for a whole population or for a sample.
- Variance CalculatorFind the variance of a data set, for a population or a sample.
- Quartiles & IQR CalculatorFind Q1, the median, Q3 and the interquartile range (IQR) of a data set.
- Weighted Average CalculatorCalculate a weighted average from values and their weights. Weights do not need to total 100.
- Z Score CalculatorFind how many standard deviations a score is from the mean, from the mean and standard deviation you enter.
- Percentile CalculatorFind the value at a chosen percentile of a data set, using inclusive linear interpolation.
- Probability CalculatorFind the probability of an event from favourable and total outcomes, as a fraction, decimal and percentage.