Statistics tools

Descriptive statistics, significance tests and regression, with the reasoning spelled out rather than just a number.

• P-Value Calculator - Calculate a p-value from a z-score or from an observed value, mean and standard deviation. Supports one- and two-tailed tests with an interpretation.
• Standard Deviation Calculator - Paste a list of numbers to get the mean, median, mode, range, variance and standard deviation, for both a sample and a whole population.
• Linear Regression Calculator - Fit a least-squares regression line to paired data. Get the slope, intercept, R-squared, correlation and a scatter plot with the fitted line.
• Chi-Square Calculator - Run a chi-square test on a contingency table or against expected frequencies. Get the statistic, degrees of freedom, p-value and an interpretation.