Covariance of Binomial Random Variables

  • Thread starter Obraz35
  • Start date
  • #1
31
0

Homework Statement


Let X be the number of 1's and Y be the number of 2's that occur in n rolls of a fair die. Find Cov(X, Y)


Homework Equations


Cov(X,Y) = E(XY) - E(X)E(Y)


The Attempt at a Solution


Both X and Y are binomial with parameters n and 1/6. Thus it is easy to find E(X) and E(Y), but for some reason finding E(XY) is really tripping me up. How does one go about finding expected values of products of binomial variables?
 

Answers and Replies

Related Threads on Covariance of Binomial Random Variables

Replies
2
Views
13K
  • Last Post
Replies
1
Views
1K
Replies
3
Views
1K
Replies
1
Views
1K
Replies
2
Views
458
Replies
1
Views
3K
Replies
12
Views
4K
  • Last Post
Replies
2
Views
388
Replies
5
Views
5K
Top