# 9.4 - Inference for Correlation

Let’s review the notation for correlation.

$$r$$: The sample correlation (Pearson’s correlation)

$$\rho$$: “rho” is the population correlation

The sample correlation is found by:

$$r=\dfrac{\sum (x_i-\bar{x})(y_i-\bar{y}) }{\sqrt{\sum (x_i-\bar{x})^2}\sqrt{\sum (y_i-\bar{y})^2}}$$

In this section, we will present a hypothesis test for the population correlation. Then, we will compare the tests and interpretations for the slope and correlation.