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The FIBS rating formula : why sqrt(n) ?

Posted By: Maik Stiebler
Date: Thursday, 15 September 2011, at 3:22 p.m.

In Response To: The FIBS rating formula : why sqrt(n) ? (Maik Stiebler)

Let me try to be less cryptic: I think a reasonable estimator of the winning percentage in the cubeless and gammonless model would be p(N, rating difference)=f(rating difference * sqrt(N)), where f is some (close-to) normal cumulative distribution function. This p, I think, would decrease like exp(-N) for large N. The FIBS formula is not a bad approximation, if you disregard the tails; and nobody really cares if p is 1e-10 or 1e-20 anyway.

Messages In This Thread

• The FIBS rating formula : why sqrt(n) ?
  Fabrice Liardet -- Tuesday, 13 September 2011, at 7:44 p.m.
  • The FIBS rating formula : why sqrt(n) ?
    Kevin Whyte -- Tuesday, 13 September 2011, at 8:58 p.m.
  • The FIBS rating formula : why sqrt(n) ?
    Michael Petch -- Tuesday, 13 September 2011, at 10:38 p.m.
    • The FIBS rating formula : why sqrt(n) ?
      Kevin Whyte -- Wednesday, 14 September 2011, at 12:39 a.m.
  • The FIBS rating formula : why sqrt(n) ?
    Timothy Chow -- Wednesday, 14 September 2011, at 5:24 p.m.
    • The FIBS rating formula : why sqrt(n) ?
      Maik Stiebler -- Thursday, 15 September 2011, at 8:27 a.m.
      • The FIBS rating formula : why sqrt(n) ?
        Maik Stiebler -- Thursday, 15 September 2011, at 3:22 p.m.
        • The FIBS rating formula : why sqrt(n) ?
          Fabrice Liardet -- Thursday, 15 September 2011, at 6:25 p.m.
          • The FIBS rating formula : why sqrt(n) ?
            Maik Stiebler -- Thursday, 15 September 2011, at 9:30 p.m.
            • The FIBS rating formula : why sqrt(n) ?
              Fabrice Liardet -- Saturday, 17 September 2011, at 8:57 a.m.
  • The FIBS rating formula : why sqrt(n) ?
    Fabrice Liardet -- Wednesday, 14 September 2011, at 8:20 p.m.
    • The FIBS rating formula : why sqrt(n) ?
      Timothy Chow -- Wednesday, 14 September 2011, at 9:21 p.m.
      • The FIBS rating formula : why sqrt(n) ?
        Michael Petch -- Wednesday, 14 September 2011, at 9:42 p.m.
  • The FIBS rating formula : why sqrt(n) ?
    Jake Jacobs -- Thursday, 15 September 2011, at 3:06 a.m.
  • The FIBS rating formula : why sqrt(n) ? Because it works!
    Rich Munitz -- Thursday, 15 September 2011, at 3:42 a.m.
    • The FIBS rating formula : why sqrt(n) ? Because it works!
      Rich Munitz -- Thursday, 15 September 2011, at 11:25 a.m.
    • The FIBS rating formula : why sqrt(n) ? Because it works!
      Timothy Chow -- Thursday, 15 September 2011, at 2:37 p.m.
  • The FIBS rating formula : why sqrt(n) ?
    Daniel Murphy -- Thursday, 15 September 2011, at 4:42 a.m.
  • The FIBS rating formula : why sqrt(n) ?
    Fabrice Liardet -- Thursday, 15 September 2011, at 6:49 p.m.
    • The FIBS rating formula : why sqrt(n) ?
      Daniel Murphy -- Thursday, 15 September 2011, at 11:15 p.m.