Explore BrainMass

# Probabilities : Marginals

Not what you're looking for? Search our solutions OR ask your own Custom question.

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

A bag contains r balls, of which 2 are red and r - 2 are black. We draw a ball at random, we write down its color, and we put it to one side (not back in the bag). We repeat the procedure r times.
Let X be the number of draws needed to obtain a red ball, and let Y be the number of draws needed to obtain a second red ball.
a. Find the probability law of the vector (X,Y) , and find its marginals.
b. Evaluate Cov(X,Y) .

https://brainmass.com/math/probability/probabilities-marginals-18556

#### Solution Preview

Please see the attached file for the complete solution.
Thanks for using BrainMass.

A bag contains balls, of which 2 are red and are black. We draw a ball at random, we write down its colour, and we put it to one side (not back in the bag). We repeat the procedure r times.
Let X be the number of draws needed to obtain a red ...

#### Solution Summary

Probailities are calculated using appropriate tables and calculations. The solution is detailed.

\$2.49