Question

How do you calculate the covariance between two discrete variables?

Answer 1

`"Cov" (X,Y) = 1/n sum_(i=1)^n x_i y_i - (1/n sum_(i=1)^n x_i)(1/n sum_(i=1)^n y_i)`

Explanation:

Consider `(x_i,y_i) forall i= 1(1)n`.

Then

`"Cov" (X,Y) = 1/n sum_(i=1)^n x_i y_i - (1/n sum_(i=1)^n x_i)(1/n sum_(i=1)^n y_i)`