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View Diary: CNN calls a five-point lead for Barack Obama in swing states a 'tie' (157 comments)

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  •  oh, good, a statistician.... so next (1+ / 0-)
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    plf515

    can you explain Bayesean probability and credibility interval? That's what on-line panels use. There is no confidence interval.

    You have 3 minutes. You may use texts and the internet.

    Go. ;-P

    "Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong remedies." - Groucho Marx

    by Greg Dworkin on Fri Sep 14, 2012 at 11:11:35 AM PDT

    [ Parent ]

    •  Sure! (2+ / 0-)
      Recommended by:
      Greg Dworkin, Twilight Jack

      In Bayesian statistics we take our "prior beliefs" into account and modify them based on new data, combining the two into a new probability called the posterior.

      We can limit the role of prior beliefs by assuming a "noninformative prior".

      Properly done, Bayesian statistics gives an answer to the right question. Improperly done, it gives nonsense. The proper question was stated in my earlier comment, and Bayesian probability and credibility intervals are about that question: Given these results, how likely is XXX?

      Of course, improperly done frequentist statistics also gives garbage, but (in my view) it is easier for two trained and capable people to get very different results when using Bayesian methods than when using frequentist ones.

      •  hence Zogby panels vs Ipsos panels (1+ / 0-)
        Recommended by:
        plf515

        makes perfect sense, actually.

        Do you want to know the kind of jar given the cookies, or the kind of cookies, given the jar? Different ways of describing the same physical thing, but different info produced..

        "Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong remedies." - Groucho Marx

        by Greg Dworkin on Fri Sep 14, 2012 at 11:46:24 AM PDT

        [ Parent ]

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