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Read to yourself. David Stenbill Monica Bigoutski Shana Tirana. Random Thoughts 2012 (COMP 066). Jan-Michael Frahm Jared Heinly. Last Class. Binomial distribution: For events with K successes in N trials Properties of a Binomial distribution : Fixed number of trials
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Read to yourself • David Stenbill • Monica Bigoutski • Shana Tirana
Random Thoughts 2012(COMP 066) Jan-Michael Frahm Jared Heinly
Last Class • Binomial distribution: For events with K successes in N trials • Properties of a Binomial distribution: • Fixed number of trials • Only outcomes are success and fail? • Same probability for success in each trial • Independent trials (no influence of previous trials to current trial)
Lessons from Reading Assignment • The probability that two events will occur can never be greater than the probability that each will occur individually.
Example • Linda (p. 22) ordering of probabilities
Steve is very shy and withdrawn, invariably helpful but with little interest in people or in the world of reality. A meek and tidy soul, he has a need for order and structure, and a passion for detail. (Kahneman, “Thinking Fast Thinking Slow”) • Is Steve more likely to be a librarian or a farmer? • There are more than 20 times the number of male farmers in the US than male librarians. So in all likelihood he will be a farmer.
Lessons from Reading Assignment • The probability that two events will occur can never be greater than the probability that each will occur individually. • “a good story is often less probable than a less satisfying … [explanation]”
Lawyers predict the end of the trial • Charges against Bill Clinton by Paula Jones (p. 25-26) • how could they tell that the lawyers predict the end more accurately if they split up the different outcomes?
Lessons from Reading Assignment • The probability that two events will occur can never be greater than the probability that each will occur individually. • “a good story is often less probable than a less satisfying … [explanation]”
Study for cancer in the US • A study of the incidence of kidney cancer in 3141 counties of the US reveals a remarkable pattern. • The counties in which the incidence of kidney cancer is the lowest are the most rural, sparsely populated and located in traditionally Republican states in the Midwest, the South and the West. • The counties in which the incidence of kidney cancer is the highest tend to be the mostly rural, sparsely populated and located in traditionally Republican states in the Midwest, the South and the West.
Lessons from Reading Assignment • The probability that two events will occur can never be greater than the probability that each will occur individually. • “a good story is often less probable than a less satisfying … [explanation]” • Missing information • Availability bias
Words • More six letter words ending with ing or with n at the 5th position (p. 28 Moldinov)
Crime Rates • What is the average crime rate of Michigan • Detroit (highest crime rate in the country) is in Michigan • actual crime rate 32.04
Identify Minor celebrities in the triangle • Mike Morse • Tori Amos • Monica Bigoutski • Enrique Forrest • Lisa Myer • Tom Clad • Ava Gardner • David Stenbill • Simon Dunn • Tim Kirkman • Shana Tirana • Joe Zimmerman • Rick Dees • Ryan Merl
Lessons from Reading Assignment • The probability that two events will occur can never be greater than the probability that each will occur individually. • “a good story is often less probable than a less satisfying … [explanation]” • Missing information • Availability bias • recallable prior knowledge influences our estimates
In Class Discussion • Math describes hard facts and is precise • Randomness can not be predicted • How can we use math to describe random events? • not simply say statistics work • does a statistic become deterministic if you model precisely and accurately?