You are Here: Home >< Maths

# Discrete Random Variables Help Please! watch

1. A discrete R.V X has probability distribution:

x -1 0 1 2 3
a b 0.1 0.3 0.2

E(X)= 0.95

Find the probability X is greater than E(X)
Find the values A and B.

Paul plays a game in which a fair coin is spun 4 times. If the number of heads is 0 or 1 Paul loses £5. If the number of heads is 2 Paul wins £5 and if the number of heads is 3 or 4 paul wins £10.

Show that P(W=-5) = 5/6

2. Sum of probabilities is always one...gives an equation for a and b.
Use the formula for E(X) to form another equation for a and b.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: March 28, 2011
Today on TSR

### Congratulations to Harry and Meghan!

But did you bother to watch?

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams