Some univariate statistics notation

Pearson’s Correlation Coefficient

Correlation: Linear association or dependence between the values of variables X and Y

Pearson’s way to measure correlation between variables \(X\) and \(Y\), denoted as \(\rho(X,Y)\):

\(E[XY] = E[X]E[Y]\)

\(\rho(X,Y) = \frac{E[XY] − E [X]E[Y]}{\sigma_X\sigma_Y}\)

Some examples of Pearson’s Correlation Coefficient: