expected value practice

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

• yes
• no

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

Find the mean (expected value) of the probability distribution.

• 85

• 83.2

• 87.1

• 84.4

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

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

The table above shows the number of cell phones per household in a small town. Find the mean round to the nearest hundredth.

• 2.80

• 2.93

• 0.10

• 0.14

Determine whether the question would be a permutation or combination: Five students from 90 will be selected to count ballots for the Class President election. How many groups of 5 students could be selected to count ballots?

• Permutation

• Combination

• Neither

Determine whether the question would be a permutation or combination: Twenty students are running for 3 different positions on student council. In how many ways can the 3 positions be filled?

• Permutation

• Combination

Determine whether the question would be a permutation or combination: To complete a quiz, you must answer 3 questions from a list of 6 questions. In how many ways can you complete the quiz?

• Permutation

• Combination

• Neither

Determine permutation or combination, then answer the question.

You are watching a horse race with 8 horses. How many ways can you pick the first, second, and third place?

Write your answer as a number. Ex: 5040