Seeing is believing!

Before you order, simply sign up for a free user account and in seconds you'll be experiencing the best in CFA exam preparation.

Basic Question 3 of 6

It is forecasted that the expected EPS for two stocks, X and Y, is $8.95 and $5. The covariance for the earnings per share for the two stocks is -32.3. What is the value for E(XY)?

A. -18.35
B. 12.45
C. 18.35

User Contributed Comments 7

User Comment
stevelaz Could someone explain this?
BayAreaPablo 1) Cov(X,Y)=E(XY)-E(X)-E(Y)
2) We know:
Cov (X,Y)=-32.3
E(X)= 8.95
E(Y)=5
E(XY)=?
3) Plug into equation 1) and solve for E(XY)
-32.3=E(XY)-8.95x5
-32.3=E(XY)-44.75
12.45=E(XY)
joe3 I feel stevelaz means how could you get the formula:
Cov(X,Y)=E(XY)-E(X)xE(Y)

Anybody can help?
viannie Cov => joint probability.

So, E(X) * E(Y) but exclude E(XY) .. therefore Cov(X,Y) = E(XY) - E(X)*E(Y)

I got it as I recognize the formula as a Joint probability. Someone please confirm though...thanks!
ThanhBUI By definition: Cov(XY)=E[(X-E(X))(Y-E(Y))]
=E[XY-YE(X)-XE(Y)+E(X)E(Y)]
=E(XY)-E(X)E(Y)-E(Y)E(X)+E(X)E(Y)
=E(XY)-E(X)E(Y)
Note: E(constant*R)=constant*E(R)
bc9115a Nice one ThanhBUI
forry9er This is an algebra problem ... not nice
You need to log in first to add your comment.
I passed! I did not get a chance to tell you before the exam - but your site was excellent. I will definitely take it next year for Level II.
Tamara Schultz

Tamara Schultz

Learning Outcome Statements

calculate and interpret the expected value, variance, standard deviation, covariances, and correlations of portfolio returns

CFA® 2024 Level I Curriculum, Volume 1, Module 5.