Correlation

Covariance is related to the correlaton between X1 and X2

• Define the corlrelation as

  • 
  • $-1\le {\rho }_{x_1{x}_2}\le 1$
    • this is called the pearson corerelation
    • • when X1 increases X2 increases
    • • when X1 increases X2 decreases
    •