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: [email protected]
> [mailto:[email protected]] On Behalf Of Visintainer PhD,
> Paul
> Sent: Wednesday, October 28, 2009 7:49 AM
> To: '[email protected]'
> 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: [email protected]
> [mailto:[email protected]] 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
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