# [Taxacom] Random taxonomy

Anthony Gill gill.anthony at gmail.com
Mon Dec 2 15:49:47 CST 2013

```Just pull the trigger Stephen.

On Tue, Dec 3, 2013 at 6:42 AM, Stephen Thorpe
<stephen_thorpe at yahoo.co.nz>wrote:

> Here's a good one: Suppose that you play Russian roulette without knowing
> how many bullets are in the revolver (which can hold up to 6 bullets). What
> is the probability of shooting yourself? Do you need to know the
> probabilities of there being n bullets in the revolver, for n=0-6? Maybe
> not, as it seems that the probability of shooting yourself depends only on
> how many bullets are actually in the revolver, so the probability would be
> 0.5 if there were 3 bullets, 1 if there were 6, etc., and nothing else is
> relevant. Oddly, though, it would also seem to be riskier if the
> probability of 4, 5, and/or 6 bullets being in the revolver was high, and
> less risky if these were low, and yet the probability of shooting yourself
> doesn't seem to depend on these probabilities! I'm confused!
>
>
> From: Hubert Turner <turner at casema.nl>
> To: Richard Zander <Richard.Zander at mobot.org>; taxacom at mailman.nhm.ku.edu
> Sent: Monday, 2 December 2013 11:04 PM
> Subject: Re: [Taxacom] Random taxonomy
>
>
> Dear Taxacomers, Dear Richard,
>
> Coincidence! I was having some fun with The Penguin Book of Curious and
> Interesting Puzzles, by David Wells (1st ed., 1992; ISBN 0-14-014875-2),
> and came across the following problems related to the one Knut Rognes
> posed.
>
>
> Problem 130: ³A correspondent writes ten letters and addresses ten
> envelopes. In how many ways can all the letters be placed in the wrong
> envelopes?²    ‹ Answer: Bernoulli posed the problem in terms of n letters.
> The general formula is:
>         n![1/2!-1/3!+1/4!-1/5!+ Š + (-1*n)/n!]
> [A complete answer is in Dorrie, 1965, p. 19]
>
> Problem 131: ³If seven letters are placed in seven envelopes randomly, how
> many letters would you expect, on average, to find in the correct
> envelopes?²    ‹ Answer: One! The answer is independent of the number of
> letters and envelopes. [Newman, 1982, p. 22]
>
>
> Hubert Turner
> biogeography
>
> Naturalis Biodiversity Center, Botany dept.,
> Leiden, The Netherlands
>
>
>
> On 02/12/2013 01:21, "Richard Zander" <Richard.Zander at mobot.org> wrote:
>
> >This is the famous "birthday problem" in combinatorics. Check any book on
> >probabilistic theory.
> >
> >_______________________
> >Richard H. Zander
> >Missouri Botanical Garden
> >PO Box 299
> >St. Louis, MO 63166 U.S.A.
> >richard.zander at mobot.org
> >
> >
> >________________________________
> >
> >From: taxacom-bounces at mailman.nhm.ku.edu on behalf of Knut Rognes
> >Sent: Fri 11/29/2013 4:24 AM
> >To: taxacom at mailman.nhm.ku.edu
> >Subject: [Taxacom] Random taxonomy
> >
> >
> >
> >Dear Taxacomers,
> >
> >
> >
> >I have a statistical problem.
> >
> >
> >
> >Consider 50 black boxes, within each is a specimen of fly. Each fly has
> >been
> >identified by someone, its name written on the inside of the box, but this
> >is invisible to you. You cannot peek inside. Each fly belong to one of 50
> >possible species.
> >
> >
> >
> >You have at your disposal the 50 possible species names for these flies,
> >each name printed on an adhesive label, the supply of printed labels for
> >each name is limitless.
> >
> >
> >
> >Here is the game: you affix a random label on the outside of a random box.
> >
> >
> >
> >Now the problem: What is the likelihood that you put a correct label on
> >the
> >box, i.e. that the name on the label matches the identity of the fly
> >within?
> >
> >
> >
> >Knut Rognes
> >
> >Oslo, Norway
> >
> >
> >
> >_______________________________________________
> >Taxacom Mailing List
> >Taxacom at mailman.nhm.ku.edu
> >http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
> >
> >The Taxacom Archive back to 1992 may be searched with either of these
> >methods:
> >
> >(1) by visiting http://taxacom.markmail.org/
> ><http://taxacom.markmail.org/>
> >
> >(2) a Google search specified as:
> >site:mailman.nhm.ku.edu/pipermail/taxacom  your search terms here
> >
> >Celebrating 26 years of Taxacom in 2013.
>
> >
> >
> >_______________________________________________
> >Taxacom Mailing List
> >Taxacom at mailman.nhm.ku.edu
> >http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
> >
> >The Taxacom Archive back to 1992 may be searched with either of these
> >methods:
> >
> >(1) by visiting http://taxacom.markmail.org/
> >
> >(2) a Google search specified as:
> >site:mailman.nhm.ku.edu/pipermail/taxacom  your search terms here
> >
> >Celebrating 26 years of Taxacom in 2013.
>
>
>
> _______________________________________________
> Taxacom Mailing List
> Taxacom at mailman.nhm.ku.edu
> http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
>
> The Taxacom Archive back to 1992 may be searched with either of these
> methods:
>
> (1) by visiting http://taxacom.markmail.org/
>
> (2) a Google search specified as:  site:
> mailman.nhm.ku.edu/pipermail/taxacom  your search terms here
>
> Celebrating 26 years of Taxacom in 2013.
> _______________________________________________
> Taxacom Mailing List
> Taxacom at mailman.nhm.ku.edu
> http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
>
> The Taxacom Archive back to 1992 may be searched with either of these
> methods:
>
> (1) by visiting http://taxacom.markmail.org
>
> (2) a Google search specified as:  site:
> mailman.nhm.ku.edu/pipermail/taxacom  your search terms here
>
> Celebrating 26 years of Taxacom in 2013.
>

--
Dr Anthony C. Gill
Natural History Curator
A12 Macleay Museum
University of Sydney
NSW 2006
Australia.

Ph. +61 02 9036 6499
Editorial Board, Species and Systematics:
http://www.ucpress.edu/series.php?ser=spsy

```