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From |
Richard Goldstein <richgold@ix.netcom.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: RE: RE: probability question |

Date |
Wed, 28 Oct 2009 13:15:23 -0400 |

thank you -- that's quite interesting and means I did not think things through sufficiently when I replied to Paul -- sorry about that Edgar Munoz wrote: > I like this approach using tabi as a calculator for this. > > r(p_exact) is P(n11 >= 3), the p-value in the Fisher's exact test > > if we calculate P(n11 >= 4), we can obtain P(n11 = 3) by difference > > > . tabi 4 0 \ 3 113, exact > > | col > row | 1 2 | Total > -----------+----------------------+---------- > 1 | 4 0 | 4 > 2 | 3 113 | 116 > -----------+----------------------+---------- > Total | 7 113 | 120 > > Fisher's exact = 0.000 > 1-sided Fisher's exact = 0.000 > > . return list > > scalars: > r(p1_exact) = 4.26072210718e-06 > r(p_exact) = 4.26072210718e-06 > r(c) = 2 > r(r) = 2 > r(N) = 120 > > > | p3exact p3plus p4plus | > |--------------------------------| > 1. | .0004815 .0004857 4.26e-06 | > > > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Visintainer PhD, > Paul > Sent: Wednesday, October 28, 2009 7:49 AM > To: 'statalist@hsphsun2.harvard.edu' > Subject: st: RE: probability question > > I'm probably thinking of this too simplistically, but wouldn't this just be > a Fisher's exact test? > > > . tabi 3 1 \ 4 112, exact /* where col = rain and row = hat */ > > | col > row | 1 2 | Total > -----------+----------------------+---------- > 1 | 3 1 | 4 > 2 | 4 112 | 116 > -----------+----------------------+---------- > Total | 7 113 | 120 > > Fisher's exact = 0.000 > 1-sided Fisher's exact = 0.000 > > . return list > > scalars: > r(p1_exact) = .0004857223202188 > r(p_exact) = .0004857223202188 > r(c) = 2 > r(r) = 2 > r(N) = 120 > > > ___________________________________ > Paul F. Visintainer, PhD > > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Richard Goldstein > Sent: Wednesday, October 28, 2009 8:38 AM > To: statalist > Subject: st: probability question > > it's been a long time since I thought about questions like this, but, as > a lead-in to a study, a client has asked the following question which he > thinks he understands and says is related to where he wants to go: > > during a consecutive period of 120 days, if it rains on 7 days and my > client wears a hat on 4 days (these are independent of any knowledge of > the weather), what is the probability that it will rain on 3 of the days > on which he is wearing a hat? > > my client swears that this is not a homework problem for him or his wife > or one of their kids! > > Rich * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: RE: RE: probability question***From:*dr kardos laszlo <l_kardos@chello.hu>

**References**:**st: probability question***From:*Richard Goldstein <richgold@ix.netcom.com>

**st: RE: probability question***From:*"Visintainer PhD, Paul" <Paul.Visintainer@baystatehealth.org>

**st: RE: RE: probability question***From:*"Edgar Munoz" <munozedg@hotmail.com>

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