Written by Scott D. Anderson
scott.anderson@acm.org
Creative Commons License
This work is licensed under a Creative Commons License.

Review

  • Red Sox probability problem: what's the probability that they will win, given that they are 2-0 in the series and assuming that the teams are equally matched?
  • Theoretical probability of winning in the double-cheating coin-flip problem.
  • Article on tort law facts (to discuss next time):
    • Are the facts on businesses suing businesses relevant? Why or why not?
    • They concentrated on trials in which plaintifff succeeds. Good call?
    • They used the median award and median punitive damage, not the mean. Good call?
    • other observations?
  • Other symmetrical distributions: Cauchy, double-exponential
  • Examples of Discrete Event simulations
  • Confidence Intervals

Two Sample tests

  • the logic of statistical tests:
    • determine H0
    • run an experiment and measure M
    • determine the probability P of M under H0
    • reject H0 if P is small
  • With more detail:
    • determine null hypothesis (H0) and alternative hypothesis (H1)
    • decide what kind of value you're going to measure
    • determine the sampling distribution under H0
    • determine the rejection region (one tail or two)
    • conduct the experiment and measure M
    • determine the probability P of M under H0, or establish a critical value for M for some conventional significance level
    • reject M if P is too small or M exceeds the critical value
  • Type I and Type II errors
  • Practical Significance versus Statistical Significance
    • If N is large enough, anything is "significant"
    • If N is too small, even real differences may not show up
  • Examples: SAT scores and pain scores
  • Testing using the Bootstrap
  • Testing using the z test
  • Testing using the t test (next time)