15 Regression Summary

Pearson's Product-Moment Correlation Coefficient, $r$, ranges from $-1$ to $1$. So $-1 \leq r \leq 1$

$r=\frac{n \sum xy- \sum x \sum y}{\sqrt{n\sum x^2-(\sum x)^2} \times \sqrt{n\sum y^2-(\sum y)^2}}$

If $|r| \gt 0.5$ then there is correlation between the data sets in which case:

$m = \frac{n \sum xy- \sum x \sum y}{n\sum x^2-(\sum x)^2}$

$c = \frac{\sum x^2 \sum y- \sum x \sum xy}{n\sum x^2-(\sum x)^2}$