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Re: Another little puzzle

From "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups comp.programming
Subject Re: Another little puzzle
Date 2022-12-21 18:55 +0100
Organization Aioe.org NNTP Server
Message-ID <tnvhb2$1vkb$1@gioia.aioe.org> (permalink)
References <puzzle-20221214131815@ram.dialup.fu-berlin.de> <algorithm-20221221130021@ram.dialup.fu-berlin.de> <tnv0ia$uein$3@dont-email.me> <874jtovgao.fsf@bsb.me.uk>

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On 2022-12-21 18:05, Ben Bacarisse wrote:

> There is a
> perfectly plausible interpretation of "average" that gives 0.5.

Not very plausible as it violates two properties of:

    min({Xi}) <= avr({Xi}) <= max({Xi})

and

    avr({C * Xi}) = C * avr({Xi})

The second one allows calculation of the average as:

    23.5 / 2 + 1.5 / 2 = ?

P.S. Of course one could reformulate the puzzle in a non-numeric way 
that would give Stefan's answer. For example this.

Let us consider vectors of same length in polar coordinates [0, 24[, 
e.g. the clock hands. An average of these vectors will be a clock hand 
again. Then, indeed, (v(23.5) + v(1.5)) / 2 = v(0.5).

P.P.S. The bounds property does not apply to vector averages. The 
scaling property does, because multiplication by a scalar works 
differently on vectors, it does not rotate the hands.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

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Thread

Re: Another little puzzle Richard Heathfield <rjh@cpax.org.uk> - 2022-12-21 13:09 +0000
  Re: Another little puzzle Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-12-21 17:05 +0000
    Re: Another little puzzle Richard Heathfield <rjh@cpax.org.uk> - 2022-12-21 17:21 +0000
    Re: Another little puzzle "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2022-12-21 18:55 +0100
      Re: Another little puzzle Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2022-12-21 19:55 +0000
        Re: Another little puzzle "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2022-12-21 22:54 +0100
          Re: Another little puzzle Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2022-12-22 00:01 +0000
            Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-21 16:05 -0800
              Re: Another little puzzle David Brown <david.brown@hesbynett.no> - 2022-12-22 16:50 +0100
                Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-22 08:30 -0800
                Re: Another little puzzle David Brown <david.brown@hesbynett.no> - 2022-12-22 22:06 +0100
                Re: Another little puzzle Richard Heathfield <rjh@cpax.org.uk> - 2022-12-22 21:30 +0000
                Re: Another little puzzle David Brown <david.brown@hesbynett.no> - 2022-12-23 13:46 +0100
                Re: Another little puzzle Y A <angel0000000001000000000000@mail.ee> - 2023-01-09 21:26 -0800
                Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-22 14:15 -0800
                Re: Another little puzzle David Brown <david.brown@hesbynett.no> - 2022-12-23 13:47 +0100
                Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-23 08:33 -0800
                Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-25 15:52 -0800
                Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-26 06:32 -0800
                Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-26 06:34 -0800
              Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-23 08:35 -0800
            Re: Another little puzzle "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2022-12-22 09:10 +0100
          Re: Another little puzzle Ǝ <angel00000100000@mail.ee> - 2022-12-30 18:18 -0800
        Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-21 14:47 -0800
          Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-23 08:35 -0800
          Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-25 15:52 -0800
            Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-26 06:32 -0800
          Re: Another little puzzle Julio Di Egidio <julio@diegidio.name> - 2022-12-26 06:33 -0800
          Re: Another little puzzle Y A <angel0000000001000000000000@mail.ee> - 2023-01-09 21:26 -0800

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