Question 1

How do you calculate a linear regression line?

Accepted Answer

The least-squares line is ŷ = a + b·x, where the slope b = (nΣxy − ΣxΣy) / (nΣx² − (Σx)²) and the intercept a = ȳ − b·x̄. This calculator computes both and shows every step.

Question 2

What does the correlation coefficient r mean?

Accepted Answer

Pearson's r measures the strength and direction of a linear relationship, from −1 (perfect negative) to +1 (perfect positive). Values near 0 mean little linear association.

Question 3

What is R-squared?

Accepted Answer

R² (the square of r) is the proportion of variation in y explained by x. For example, R² = 0.81 means 81% of the variability in y is explained by the regression line.

Linear Regression & Correlation Calculator

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