Linear Regression
Regression equation
y = 1.990909x + 0.08
Slope (m)
1.990909
Intercept (q)
0.08
R² coefficient
0.999529
Correlation (r)
0.999764
Covariance
18.25
FAQ
Simple linear regression
What does R² indicate?
R² (coefficient of determination) measures the fraction of Y variance explained by the linear model. Ranges 0–1: 1 = perfect fit, 0 = no linear relationship.
Difference between correlation and regression?
Correlation measures strength and direction of linear relation (symmetric, -1 to +1). Regression models Y as a function of X and gives a predictive equation.
How many points does a linear regression need?
At least two, and the X and Y series have to be the same length. With fewer than two values, or series of different length, the calculation stops and a warning appears.
What does the R² coefficient mean?
R² is the share of the variation in Y explained by the regression line, and it runs from 0 to 1. Close to 1 the points sit almost on the line, close to 0 the linear relation is weak.
How should the X and Y values be entered?
In two separate fields, split by comma, space or semicolon. Decimals use a full stop, and anything that is not a number is ignored by the calculation.