Pop Quiz 12.5 (A2)

Given the probability model in the table below, what is the expected value of the random variable?
  X        50          20        5
P(X)     0.1         0.3      0.6

• 14
• 4.67
• 5
• 7.5

If the expected value is negative, are you expected to win?

• yes
• no

A coin is flipped 3 times. If you get tails once you get $5, tails twice you get $15, and tails on all three flips you get $40. What is the expected amount of money you will get?

• $12.50
• $5
• $7.50
• $10

Eva flips a coin. If she gets heads, she wins $4. If she gets tails, she loses $3. What is her expected value of a coin flip?

• $1

• $0.50

• -$0.50

• $0

Suppose you buy a ticket for $6 out of a lottery of 1000 tickets where the prize for the one winning is to be $800. How much money do you take home (after paying for it)?

• $800

• -$6.50

• -$6

• -$5.20

A fair, 6-sided dice is thrown 18 times.

Roughly how many times would you expect the number 6 to come up?

• 1

• 3

• 6

A box contains 12 red, 20 green and 8 yellow sweets.

One is picked out at random then placed back 80 times.

Roughly how many times would you expect him to pick up a yellow sweet?

• 8

• 12

• 16

• 24

You roll a standard die. You win $12 if you roll a six, $6 if you roll a one, and $0 if you roll anything else. What is the expected value of a single roll?

• $3

• $18

• $9

• $2

You are going to pick a marble from the container, put it back, and take another. If you get two yellow, you win $200. If you get one yellow on either pick, you get $50. If you pick two red, you get $100. Anything else earns $0. What is the expected value of this game?

• $60

• $33.33

• $44.33

• $20