Covariance given joint probability function

SS 2, Reading #8 LOS 8L Calculate and interpret covariance given a joint probability function Will someone please help me out here, what is your understanding of the above question? more importantly any ideas on how this can be easily understood to answer the question in a timely manner? thx :slight_smile:

It’s hard to think of any problems like this you could do in a couple of minutes. Maybe a 2x2 box? E.g. X 1 2 1 0.2 0.1 y 2 0.3 0.4 Cov(X,Y) = EXY -EXEY EXY = 1*0.2+2*0.1+2*0.3 + 4*0.4 = 2.6 EX = 1*0.5+2*0.5 = 1.5 EY = 1*0.3 + 2*0.7 = 1.7 Cov(X,Y) = 2.6 - 1.5*1.7 = (whatever too lazy) edit: My joint probability box came out terrible without spaces (we need to be able to enter html here). P(X=1,Y=1) = 0.2, P(2, 1) = 0.1, P(1,2) = 0.3, P(2,2) = 0.4

Thx for the reply, i am trying to understand your probability box :slight_smile: