Combining Expected Value

• 0.45
• 0.65
• 1.00
• 1.44

• Box A
• Box B
• Box A or B, but not C
• All boxes offer the same expected winnings

A car dealer buys hybrids for $21,000 each and sells them for $24,500 each. Find his expected weekly profit.

• $2,380

• $5,355

• $8,109

• $37,485

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

A small store keeps track of the number X of customers that make a purchase during the first hour that the store is open each day. Based on the records, X has the following probability distribution. What is the average number of customers that the owner can expect to make a purchase in the first hour of opening?

• 0.2

• 1.4

• 2.0

• 3.0

A game consists of rolling a colored die with three red sides, two green sides, and one blue side. A roll of a red loses. A roll of green pays $2.00. A roll of blue pays $5.00.   The charge to play the game is $2.00. What is the expected value

• $0

• -$0.50

• $.67

• $-1.50

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

• yes

• no

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 ticket is $800. What is the expected value (after paying for the ticket)?

• $800

• -$6.50

• -$6

• -$5.20

A student group sells 500 raffle tickets for $2 each. At the drawing the top prize will be a gift certificate for $100. Second prize will be a $50 gift card and there will be five 3rd prizes, each a $20 gift card. Do you expect to win or lose (on average)? How much?

• lose an average of $5.50

• lose an average of $1.50

• win an average of $2.00

• lose an average of $10.00