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How many rolls before you are better than 50% to... Ray gave the formula!

Posted By: Taper_Mike
Date: Thursday, 8 September 2011, at 11:39 p.m.

In Response To: Average number of rolls to roll 66 (Ray Kershaw)

How Many Rolls before You Are the Favorite? Leo Bueno showed his brute force method to find the number of rolls it takes before you become a favorite to roll a 66. Ray Kershaw then gave the general formula that can be applied many other similar questions. Against a five-point board, for instance, how many rolls or fractional rolls does it take before you a favorite to enter? Set p = 11/36 in the boldface forumla below to get the answer. Ray's post is repeated below: Correct. You solve using logarithms. (1-p)^n = 0.5 n * log(1-p) = log (0.5) n = log (0.5) / log(1-p) n = 24.6 when p = 1/36 Mike

Messages In This Thread

• Average number of rolls to roll 66
  Raj Jansari -- Tuesday, 6 September 2011, at 9:20 a.m.
  • Average number of rolls to roll 66
    Stick -- Tuesday, 6 September 2011, at 9:25 a.m.
    • Average number of rolls to roll 66
      Raj Jansari -- Tuesday, 6 September 2011, at 9:27 a.m.
      • Average number of rolls to roll 66
        falafel -- Tuesday, 6 September 2011, at 9:33 a.m.
        • Average number of rolls to roll 66
          Art Grater -- Tuesday, 6 September 2011, at 9:57 a.m.
          • Average number of rolls to roll 66
            Raj Jansari -- Tuesday, 6 September 2011, at 10:01 a.m.
            • Average number of rolls to roll 66
              Bob Koca -- Tuesday, 6 September 2011, at 11:06 a.m.
              • No hand waving - Bob gave proof
                Taper_Mike -- Tuesday, 6 September 2011, at 7:52 p.m.
              • Average number of rolls to roll 66
                Jason Lee -- Friday, 9 September 2011, at 12:39 a.m.
                • Average number of rolls to roll 66
                  Joe Russell -- Friday, 9 September 2011, at 2:31 p.m.
                  • Average number of rolls to roll 66
                    Jason Lee -- Saturday, 10 September 2011, at 12:57 a.m.
                    • Average number of rolls to roll 66
                      Bob Koca -- Saturday, 10 September 2011, at 3:02 a.m.
                      • Average number of rolls to roll 66
                        Casper van der Tak -- Saturday, 10 September 2011, at 7:51 a.m.
                    • Average number of rolls to roll 66
                      Joe Russell -- Saturday, 10 September 2011, at 4:33 a.m.
                • Average number of rolls to roll 66
                  Daniel Murphy -- Saturday, 10 September 2011, at 12:14 a.m.
            • Average number of rolls to roll 66
              Ray Kershaw -- Tuesday, 6 September 2011, at 12:44 p.m.
              • Average number of rolls to roll 66
                Raj Jansari -- Tuesday, 6 September 2011, at 1:06 p.m.
                • Average number of rolls to roll 66
                  Ray Kershaw -- Tuesday, 6 September 2011, at 1:37 p.m.
                  • Average number of rolls to roll 66
                    Raj Jansari -- Tuesday, 6 September 2011, at 2:02 p.m.
                  • Average number of rolls to roll 66
                    leobueno -- Tuesday, 6 September 2011, at 9:22 p.m.
                    • Average number of rolls to roll 66
                      Ray Kershaw -- Wednesday, 7 September 2011, at 9:15 a.m.
                      • How many rolls before you are better than 50% to... Ray gave the formula!
                        Taper_Mike -- Thursday, 8 September 2011, at 11:39 p.m.
          • Average number of rolls to roll 66
            Art Grater -- Tuesday, 6 September 2011, at 10:05 a.m.
        • An old bar bet
          Timothy Chow -- Tuesday, 6 September 2011, at 2:28 p.m.
    • Average number of rolls to roll 66
      John O'Hagan -- Tuesday, 6 September 2011, at 3:48 p.m.