Let X and Y be random variables with means µX and µY . The covariance of...

70.2K

Verified Solution

Question

Basic Math

Let X and Y be random variables with means µX and µY . Thecovariance of X and Y is given by, Cov(X, Y ) = E[(X ? µX)(Y ? µY)]

a) Prove the following three equalities: Cov(X, Y ) = E[(X ?µX)Y ] = E[X(Y ? µY )] = E(XY ) ? µXµY

b) Suppose that E(Y |X) = E(Y ). Show that Cov(X, Y ) = 0 (hint:use the law of interated expectations to show that E(XY ) = µXµY ).In this case, what is the correlation coefficient ? between X and Y, equal to?

c) Suppose that Cov(X, Y ) = 0. Does this imply that X and Y areindependent? Explain your reasoning.

Answer & Explanation Solved by verified expert
4.0 Ratings (560 Votes)
    See Answer
Get Answers to Unlimited Questions

Join us to gain access to millions of questions and expert answers. Enjoy exclusive benefits tailored just for you!

Membership Benefits:
  • Unlimited Question Access with detailed Answers
  • Zin AI - 3 Million Words
  • 10 Dall-E 3 Images
  • 20 Plot Generations
  • Conversation with Dialogue Memory
  • No Ads, Ever!
  • Access to Our Best AI Platform: Flex AI - Your personal assistant for all your inquiries!
Become a Member

Other questions asked by students