Dice probability

Question

You roll a die. If you roll an odd number, you will receive as many dollars as the number rolled. If you roll an even number, you will lose as many dollars as the number rolled. What are your expected winnings?

Answer 1

E=(1/6)(1)+(1/6)(-2)+(1/6)(3)+(1/6)(-4)+(1/6)(5)+1/6(-6)

E=(1/6) (1-2+3-4+5-6)=-3/6=-1/2

Answer 2

Hi Again Chris;

The die has six sides.

Three are of an even (loosing) number: 2, 4, 6

Three of an an odd (winning) number:  1, 3, 5

The even numbers are greater.

 

The average even (loosing) number is 4.

The average odd (winning) number is 3.

 

On average, you can expect to loose half-a-dollar.