## 2.6 Pearson’s Correlation Coefficient

### Meaning and Calculation

**Pearson’s correlation coefficient**provides a quantitative method for determining the strength and direction of a numerical association.- It is denoted by a lower-case r and can be calculated using the following formula:

r=\frac{\sum_{i=1}^{n}\left(x_{i}-\bar{x}\right)\left(y_{i}-\bar{y}\right)}{(n-1) s_{x} s_{y}}

Where s_{x} and s_{y} are the standard deviations of the explanatory and response variables, respectively.