Linear Regression & Correlation

Find the line of best fit, the correlation coefficient r and predictions from paired data, with sums and slope calculated. Try “best fit line for (1,2), (2,4), (3,5), (4,4), (5,6)”.

Try an example:

How the Linear Regression & Correlation works

  1. Compute the means and the sums Σxy, Σx² and Σy².
  2. Slope b = Sxy ÷ Sxx and intercept a = ȳ − b·x̄.
  3. Write y = a + bx, compute r and use the line to predict.

Frequently asked questions

What does the correlation coefficient r mean?

r runs from −1 to 1: near ±1 is a strong linear relationship, near 0 is little or none.

Does correlation prove causation?

No. Two variables can move together without one causing the other.

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