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Money Duck

by Dan Meyer


Act One

  • Dan Meyer

    Dan Meyer

    May 05, 2014

    What price would you pay for the Money Duck?

  • Teacher note
    Have students share their responses with their neighbors. Find the high and low in the class.

Act Two

  • 1.

    What information would be useful to know here?

  • 2.

    What do you think this mathematical model is trying to tell you about Money Ducks?

  • ImageProbability Distribution Image
  • 3.

    Which of these probability distributions are possible and which are impossible? Why? How do you know?

  • ImageImpossible & Possible Distributions
  • 4.

    If you're selling Money Ducks for $5, why is each of these distributions bad for business?

  • ImageBad for Business Distributions
  • 5.

    Make up a price for each of these distributions so that the buyer and seller won't gain or lose money over the long run.

  • ImagePrice the Distributions
  • Teacher note
    This is your moment to teach Expected Value. The ball is on the tee. They've done a lot of informal thinking about EV. Now you can formalize it.
  • 6.

    What is the expected value of each of these distributions?

  • ImageCalculate Expected Value
  • FileHandout w/ All These Questions

Act Three

  • Teacher note

    1. It tells you all the possible events for the Money Duck and the likelihood of each event.

    2. B and C are impossible because the total probability exceeds 100%. D is impossible because the total probability doesn't reach 100%.

    3. A is bad for business because people will eventually stop buying your ducks. B is bad for business because you're giving away a lot of $50s for only $5.

    4. Answers will vary.


    A: $6.5

    B: $30.60

    C: $21.35

    D: $17.20


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