how to estimate anything

Download How to Estimate Anything

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  • HOW TO ESTIMATE ANYTHINGLearning Night - 01/21/15

  • WHAT IM TALKING ABOUT TODAY What is a Fermi Estimation?

    An example to get us going

    Some tips and tricks

    Try it yourself!

    Skeptical?

  • EVER WONDER HOW MANY OR HOW OFTEN SOMETHING HAPPENS?

  • HOW MANY PIANO TUNERS ARE IN SAN FRANCISCO?

  • PIANO TUNERS IN SF 1M people in SF

    2 people per household

    1/20 households have a piano

    each piano tuned once a year

    2 hours to tune a piano

    tuners work full time for 40 hours a week

  • THE MATH

    1M people / 2 people per household = 500K households

    500K * 1 / 20 pianos/household = 25 000 pianos = 25 000 piano tunings per year

    1 hour to tune a piano = 100 000 piano tuning hours

    100 000 hours / 2 000 hours per piano tuner = ~50 piano tuners!

  • USEFUL FOR

    Interviews!

    Satisfying personal curiosity

    Trying to figure out whether or not Maroon 5 really crashed all those weddings

  • TACTICS

    Top down vs. Bottoms up

    Give a range!

    Easy numbers = Good numbers

    Key is make assumptions based on what you know

  • HOW MANY PEOPLE ARE NAMED JONATHAN IN THE WORLD?

  • LOL. WHAT A DOUCHE.

    Jonathan is a Male name

    50% of population is Male

    Only Westernized civilizations will name kids Jonathan (2B people)

    1/16 Males named some variation of Jonathan (Jon, John, Johnathan etc)

    3B * 50% * 1/16 = 62.5M people named Jonathan

  • SKEPTICAL?

    Fermi is for

    quick estimates

    magnitude

    starting points

  • "FERMI ESTIMATES WORK BECAUSE THE ESTIMATIONS OF THE INDIVIDUAL TERMS ARE OFTEN CLOSE TO

    CORRECT, AND OVERESTIMATES AND UNDERESTIMATES HELP CANCEL EACH OTHER OUT. "