Topic 4.7 - Expected value

Choose an American household at random. What is the expected number of cars for that household?

• 1.75
• 1.84
• 2.00
• 2.50

In a certain community, 30% of households have 1 child, 43% have 2 children, and 27% have 3 children. If a household is selected at random, what is the expected number of children in that household?

(hint: A probability table may be helpful.)

• 2.00
• 2.13
• 1.97
• 1.27

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

(hint: first, find out how much he makes on each car!)

• $2,380
• $5,355
• $8,109
• $37,485

Using the probability model given, what is the expected value of the random variable?

• 14
• 4.67
• 5
• 7.5

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

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

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

All probability distributions will add to _ , or 100%

Determine which of the following distribution is NOT a probability distribution.

• A

• B

• C

• D