Expected Value

Suppose there’s a game where the player rolls a die, and either wins or loses money according to these rules: If you roll a 1,2 or 3, you lose 5 dollars. If you roll a 4 or a 5, you win 1 dollar. If you roll a 6, you win 10 dollars. In the long run, how much are you expected to make if you play this game?

• -.50

• .50

• 3

• -3

Each night, your best friend phones you either 1, 2, or 3 times. There is a 35% of getting one call, a 40% chance of getting two calls, and a 25% chance of getting three calls. What is the expected number of phone calls?

• -1.8

• 1.8

• 1.9

• -1.9

Tags

CCSS.HSS.MD.A.2

Consider the number of loudspeaker announcements per day at school. Suppose there’s a 15% chance of having 0 announcements, a 30% chance of having 1 announcement, a 25% chance of having 2 announcements, a 20% chance of having 3 announcements, and a 10% chance of having 4 announcements. Find the expected value of the number of announcements per day.

• 1.8

• -1.8

• 2

• -2

Phoenix tells Omar she will give him $1 if he rolls a number divisible by three or $3 dollars if he rolls a five on a single die. If Omar rolls a one, he needs to give Phoenix $5. How much can Omar “expect” to make in the long run if he plays this game with Phoenix?

• 0

• 1.5

• -1.5

• -1

Five hundred raffle tickets are sold for $2 each. One prize of $400 is to be awarded. Michelle purchases one ticket. Determine her expected value.

• -1.2

• 1.2

• 0

• 2.792