From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS53758 23.128.96.0/24 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_LOW, SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id 90FD71F5AE for ; Sun, 16 May 2021 21:08:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233810AbhEPVIg (ORCPT ); Sun, 16 May 2021 17:08:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233721AbhEPVIf (ORCPT ); Sun, 16 May 2021 17:08:35 -0400 Received: from mail-wr1-x429.google.com (mail-wr1-x429.google.com [IPv6:2a00:1450:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AF32C061573 for ; Sun, 16 May 2021 14:07:19 -0700 (PDT) Received: by mail-wr1-x429.google.com with SMTP id i17so4332255wrq.11 for ; Sun, 16 May 2021 14:07:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Mtp3KKtbQpqMnRUpG66ddXQ9aP3rNHdtMjWWdzvIxMw=; b=GpijMtqLfWr2PoYTQgg8JEAfHlOhIZzDyn5bEqw+KR0ZkkZYwFtssCoPcQ6viywicD fv9tbbAFOjkVOlV9vnN2M/qJcsvC8Fso7Kv4FG0b3p1po7H7p0s8eMBWTYGYDEJt2kgd MQWuJjalmdwM15KlWiraIID/LDXiHHun/7kvCrpC7amULHXD7PAmknEEGzuHe9yBrtI3 wOH6HICTFJc2j9EpSgYY3IIYbJ5kLyR0eR0wJX5KNvgQATT8vwqxNPk+M6jLGmj8z+qE lcl9pxuKQWFRgS5GB5AWO8krMoa0Kgkgb8cfeWsw65u3vIY05DM7UtJHfRxvpD/laZej yrHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Mtp3KKtbQpqMnRUpG66ddXQ9aP3rNHdtMjWWdzvIxMw=; b=CGfTTGbJjiXiMeuKvDn0M9DTqWrXF53nagutgPl2KfKDZRGYS9MYKL8dvyUj5Cx8Fs llpeoZkvyTY73geV1qBfr31E85duukxi2X2EVwun0mYc7l2pKUW9rVYeFzhAQAmPk0xC o0BogX7M2Tdy0+GWc2tdTeutx1l6VzzbW1h9ib+unIGGQjcLYOODJVrzfGHPA6GNvr9J GtAaAGYajXEArPEfJYUGCqWTEPGnnS8uezUMJnXPEpXrUShsOcNeT7a7Z0BLi9bL+kSr U/zdGoO9ZyJgdwczIRUgUz569tz0iED65Ew6GyRg/kF12o20zUywXCz1PC4tVEVfdi4n hE6g== X-Gm-Message-State: AOAM531jtgQRqASXc4lRuW06RfIy++Nw5U1Y7iIOqxYcvvtEWA2CwCc4 9jTzonLltfVoU4NuZoG29bkWJceTxIyOLcpsEkw= X-Google-Smtp-Source: ABdhPJzJkU9LVHWqyVO86wczHwYvroIPWwPMYdjdUZSZHqlYU6LGt82T16HMS1csesq0eBhDFV9oPJtGHJdLAenHLwE= X-Received: by 2002:a5d:5184:: with SMTP id k4mr25047741wrv.84.1621199237651; Sun, 16 May 2021 14:07:17 -0700 (PDT) MIME-Version: 1.0 References: <1dc7877e-adb4-e3f5-3b59-bd45f9673596@gmail.com> <60a1699eedcd4_109fc7208e1@natae.notmuch> <7ab75f6a-14a8-1aa7-ad0-20f484e2c8@crashcourse.ca> In-Reply-To: <7ab75f6a-14a8-1aa7-ad0-20f484e2c8@crashcourse.ca> From: Felipe Contreras Date: Sun, 16 May 2021 16:07:06 -0500 Message-ID: Subject: Re: [PATCH] describe-doc: clarify default length of abbreviation To: "Robert P. J. Day" Cc: Bagas Sanjaya , =?UTF-8?Q?Anders_H=C3=B6ckersten_via_GitGitGadget?= , Git , =?UTF-8?Q?Anders_H=C3=B6ckersten?= Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Sun, May 16, 2021 at 2:00 PM Robert P. J. Day wrote: > On Sun, 16 May 2021, Felipe Contreras wrote: > > Bagas Sanjaya wrote: > > > What is the birthday paradox then? > > > > It's a probability fact that goes against common sense. In a romm > > with 23 people you are 50% likely to find two people with the same > > birthday. > > > > https://en.wikipedia.org/wiki/Birthday_problem > > i've had to explain the logic behind this to people who really have > a tough time understanding this, and it's a concept that applies in a > lot of places (surprisingly). Indeed. Very very few people actually understand probability. Any intuition you have is almost always wrong. Even professional probabilists get probability wrong consistently. I've found it's safer and easier to not trust my intuition, write code, and that way get the probability (also called Monte Carlo method). I have a git repository with tricky simulations and I actually had written one for the birthday paradox, but I had not pushed it. Now I have [1]. The actual code is just two lines: birthdays = Array.new($n) { rand(365.25) } birthdays.any? { |e| birthdays.count(e) > 1 } Yet our brain somehow has trouble figuring out the approximate result of that computation. Cheers. [1] https://github.com/felipec/simulation/blob/master/examples/birthday -- Felipe Contreras