Linear Regression Calculator

This tool fits a straight line to paired data using ordinary least squares, the same line a graphing calculator draws as the line of best fit. Paste your x values and your y values as two lists of the same length and it returns the equation, the slope, the intercept, the correlation r and r squared. A second mode uses that line to predict y at an x you choose. A strong r squared says the line describes the data well, not that x causes y, and predicting beyond the range of your data is guesswork.