Question

If r = 0.5, σ_x = 1 and σ_y = 4, then find Cov.(X,Y).

Answer 1

Given, r = 0.5, σ x = 1 and σ y =  4 

We have r = `("Cov" ("x" . "y"))/(sigma  "x" . sigma  "y")`

`=> 0.5 = ("Cov" ("x" . "y"))/(1 xx 4)`

`=> 1/2 = ("Cov" ("x" . "y"))/4`

⇒ Cov . (x , y) = `4/2 = 2`