CalcPine

Statistics Calculators

A free set of statistics tools for students, researchers and analysts — descriptive spread, standard scores, sampling, and correlation. Each shows the formula, a worked example and the assumptions behind the result.

Spread & descriptive

Standard Deviation Calculator New Variance Calculator New Coefficient of Variation Calculator New RSD Calculator Average (Mean) Calculator

Scores & intervals

Z-Score Calculator New Standard Error Calculator New Confidence Interval Calculator New

Sampling & relationships

Margin of Error Calculator New Sample Size Calculator New Correlation Coefficient Calculator New

From data set to conclusion

These tools cover the calculations that recur across statistics coursework and applied research: summarising spread with standard deviation, variance and coefficient of variation; standardising values with z-scores; quantifying the precision of an estimate with the standard error and confidence interval; planning a survey with the margin of error and sample size; and measuring association with the Pearson correlation coefficient. Every calculator states the equation it uses and works a numeric example so you can check the method as well as the answer.

Frequently asked questions

When do I use n versus n − 1?
Use n − 1 (sample) when your data is a sample of a larger population, which is the usual case. Use n only when you have the entire population.
What's the difference between standard deviation and standard error?
Standard deviation measures the spread of individual values; standard error measures how precisely the sample mean estimates the true mean, and shrinks as the sample grows.
Does a high correlation mean one thing causes the other?
No. Correlation measures association, not causation — a third variable may be driving both.