June 24, 2015 getting variance from known correlation Leave a comment Suppose X and Y have the same distribution, and Corr(X,Y) = -0.5. Find V[X+Y]. I know that Corr(X,Y)*SD[X]SD[Y] = Cov(X,Y) and also V[X+Y] =… Advertisements Share this:TwitterFacebookGoogleLike this:Like Loading... Related Posted by ronaldconnelly423.