By definition of variance
where so the proof just substitutes into this formula where
Can you follow it now?
Hi guys. I'm not quite sure if this belongs in here but here goes.
We must prove that for is perfectly negatively correlated.
Here is what I know. I know that a correlation coefficient
I have the answer but i do not get where or why there is an E in there. If anyone could explain this it would be fantastic. Thank you