BGonline.org Forums

Confidence Interval Overlap vs Joint Standard Deviation (long)

Posted By: Bob Koca
Date: Saturday, 31 October 2009, at 7:30 p.m.

In Response To: Confidence Interval Overlap vs Joint Standard Deviation (long) (neilkaz)

"What we see here is that if the two 95% CI's don't overlap or if they even touch we have at least 99% confidence. "

No.

Your calculations were assuming that the std dev for each play individually was the same. Suppose though that we have already rolled out play A a LOT and have equity of .60 with s.d. of .001. We then start rolling out play B and after a while we have equity of .65 with std dev. .024 The 95% CI do not overlap but the joint CI is just a little bit more than 95%.

I also point out that the calculation of joint SD makes an independence assumption which I don't think is warranted.

Messages In This Thread

• Confidence Interval Overlap vs Joint Standard Deviation (long)
  neilkaz -- Saturday, 31 October 2009, at 5:13 p.m.
  • Confidence Interval Overlap vs Joint Standard Deviation (long)
    Timothy Chow -- Saturday, 31 October 2009, at 5:30 p.m.
  • Confidence Interval Overlap vs Joint Standard Deviation (long)
    Tom Keith -- Saturday, 31 October 2009, at 5:51 p.m.
    • Confidence Interval Overlap vs Joint Standard Deviation (long)
      Rich Munitz -- Sunday, 1 November 2009, at 3:19 a.m.
  • Confidence Interval Overlap vs Joint Standard Deviation (long)
    Bob Koca -- Saturday, 31 October 2009, at 7:30 p.m.
    • Confidence Interval Overlap vs Joint Standard Deviation (long)
      neilkaz -- Saturday, 31 October 2009, at 9:20 p.m.
      • Confidence Interval Overlap vs Joint Standard Deviation (long)
        Bob Koca -- Saturday, 31 October 2009, at 9:31 p.m.
      • Confidence Interval Overlap vs Joint Standard Deviation (long)
        Timothy Chow -- Sunday, 1 November 2009, at 12:21 a.m.
  • A better approch?
    eXtreme Gammon -- Sunday, 1 November 2009, at 4:02 a.m.
    • A better approch?
      neilkaz -- Sunday, 1 November 2009, at 4:32 a.m.
    • A better approch?
      MaX -- Sunday, 1 November 2009, at 1:19 p.m.
    • A better approch?
      MaX -- Sunday, 1 November 2009, at 1:22 p.m.
    • A better approch?
      Timothy Chow -- Sunday, 1 November 2009, at 5:37 p.m.
      • A better approch?
        eXtreme Gammon -- Sunday, 1 November 2009, at 6:12 p.m.
        • A better approch?
          Bob Koca -- Sunday, 1 November 2009, at 7:36 p.m.
          • A better approch?
            Tom Keith -- Sunday, 1 November 2009, at 8:38 p.m.
            • A better approch?
              Chuck Bower -- Monday, 2 November 2009, at 1:20 a.m.
              • A better approch?
                Jason Lee -- Monday, 2 November 2009, at 2:24 a.m.
                • A better approch?
                  Chuck Bower -- Monday, 2 November 2009, at 3:06 p.m.
              • A better approch?
                Timothy Chow -- Monday, 2 November 2009, at 6:56 p.m.
        • A better approch?
          Maik Stiebler -- Sunday, 1 November 2009, at 10:05 p.m.
        • A better approch?
          MaX -- Monday, 2 November 2009, at 10:15 a.m.
          • A better approch?
            Timothy Chow -- Monday, 2 November 2009, at 6:47 p.m.
            • A better approch?
              MaX -- Tuesday, 3 November 2009, at 8:18 a.m.
          • A better approch?
            eXtreme Gammon -- Monday, 2 November 2009, at 7:26 p.m.
            • A better approch?
              MaX -- Thursday, 12 November 2009, at 12:56 p.m.
        • A better approch?
          Timothy Chow -- Monday, 2 November 2009, at 6:40 p.m.
          • A better approch?
            Tom Keith -- Monday, 2 November 2009, at 7:28 p.m.
            • A better approch?
              Timothy Chow -- Monday, 2 November 2009, at 10:10 p.m.
              • A better approch?
                Tom Keith -- Tuesday, 3 November 2009, at 12:14 a.m.
                • A better approch?
                  Timothy Chow -- Tuesday, 3 November 2009, at 1:29 a.m.
                  • A better approch?
                    Maik Stiebler -- Tuesday, 3 November 2009, at 7:18 a.m.
                    • A better approch?
                      Timothy Chow -- Tuesday, 3 November 2009, at 4:17 p.m.
                      • A better approch?
                        Tom Keith -- Tuesday, 3 November 2009, at 5:23 p.m.
                        • A better approch?
                          Timothy Chow -- Tuesday, 3 November 2009, at 5:37 p.m.
                          • Aren't you two just particpating in the 250 year old fracas?
                            Chuck Bower -- Tuesday, 3 November 2009, at 6:19 p.m.
                            • Aren't you two just particpating in the 250 year old fracas?
                              Timothy Chow -- Tuesday, 3 November 2009, at 7:55 p.m.
                              • Aren't you two just particpating in the 250 year old fracas?
                                Bob Koca -- Tuesday, 3 November 2009, at 8:29 p.m.
                            • Aren't you two just particpating in the 250 year old fracas?
                              Tom Keith -- Wednesday, 4 November 2009, at 12:11 p.m.
                      • A better approch?
                        Maik Stiebler -- Wednesday, 4 November 2009, at 8:40 p.m.
                        • A better approch?
                          Timothy Chow -- Wednesday, 4 November 2009, at 10:09 p.m.
                          • A better approch?
                            Maik Stiebler -- Wednesday, 4 November 2009, at 10:51 p.m.
                            • A better approch?
                              Maik Stiebler -- Wednesday, 4 November 2009, at 11:57 p.m.
                            • A better approch?
                              Timothy Chow -- Thursday, 5 November 2009, at 6:52 a.m.
                              • A better approch?
                                Maik Stiebler -- Thursday, 5 November 2009, at 7:25 a.m.
                                • A better approch?
                                  Timothy Chow -- Thursday, 5 November 2009, at 3:37 p.m.
                                  • A better approch?
                                    Maik Stiebler -- Thursday, 5 November 2009, at 9:19 p.m.
                                    • A better approch?
                                      Maik Stiebler -- Thursday, 5 November 2009, at 9:42 p.m.
          • A better approch? [LONG]
            MaX -- Thursday, 5 November 2009, at 3:04 p.m.
            • A better approch? [LONG]
              Timothy Chow -- Thursday, 5 November 2009, at 3:47 p.m.
            • A better approch? [LONG]
              Maik Stiebler -- Thursday, 5 November 2009, at 10:01 p.m.
              • A better approch? [LONG]
                MaX -- Friday, 6 November 2009, at 3:31 p.m.
                • A better approch? [LONG]
                  Maik Stiebler -- Saturday, 7 November 2009, at 5:52 p.m.
                  • A better approch? [LONG]
                    MaX -- Monday, 9 November 2009, at 12:39 p.m.
                    • A better approch? [LONG]
                      Maik Stiebler -- Monday, 9 November 2009, at 10:59 p.m.
                      • A better approch? [LONG]
                        MaX -- Tuesday, 10 November 2009, at 1:33 p.m.
        • A better approch?
          Tom Keith -- Thursday, 5 November 2009, at 10:23 p.m.
          • A better approch?
            MaX -- Friday, 6 November 2009, at 12:35 p.m.
    • A better approch?
      Bob Koca -- Sunday, 1 November 2009, at 7:45 p.m.
      • A better approch?
        eXtreme Gammon -- Sunday, 1 November 2009, at 10:03 p.m.
        • A better approch?
          Bob Koca -- Sunday, 1 November 2009, at 10:30 p.m.
    • A better approch?
      Mislav Radica -- Monday, 2 November 2009, at 12:59 a.m.
      • A better approch?
        eXtreme Gammon -- Monday, 2 November 2009, at 1:58 a.m.
        • A better approach?
          eXtreme Gammon -- Monday, 2 November 2009, at 2:00 a.m.
        • A better approch?
          MaX -- Monday, 2 November 2009, at 10:19 a.m.
        • A better approch?
          Mislav Radica -- Monday, 2 November 2009, at 12:55 p.m.
          • The different approachs-give us a choice
            Mislav Radica -- Monday, 2 November 2009, at 1:18 p.m.
        • A better approch?
          misja -- Monday, 2 November 2009, at 7:36 p.m.
    • A better approch?
      Neil Robins -- Tuesday, 3 November 2009, at 9:39 p.m.