Measure a Relationship

These calculators measure how variables are related. Pearson and Spearman correlation give the strength of a relationship between two measured variables, linear and multiple regression fit an equation you can use for prediction, and the odds ratio compares two groups from a 2×2 table of counts.

Tools in this group

• Correlation Coefficient Calculator (Pearson r) — Paste x, y pairs to get Pearson's r, r², the p-value and a confidence interval, with the sums and a scatter plot.
• Linear Regression Calculator — Paste x, y pairs to get the least squares regression line ŷ = a + b·x, R², tests for slope and intercept and a prediction.
• Multiple Regression Calculator — Paste a table with a header row, choose the response column and get the fitted equation, coefficient tests, R² and VIF.
• Odds Ratio Calculator — Enter the four counts of a 2×2 table to get the odds ratio with its confidence interval, relative risk, risk difference and p-values.
• Spearman Rank Correlation Calculator — Paste x, y pairs to get Spearman's rho with mid-ranks for ties, the p-value and a table of ranks, d and d².