From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.50.254.161 with SMTP id aj1mr2804028igd.6.1428054411571; Fri, 03 Apr 2015 02:46:51 -0700 (PDT) X-Received: by 10.140.97.137 with SMTP id m9mr14125qge.12.1428054411410; Fri, 03 Apr 2015 02:46:51 -0700 (PDT) Path: border1.nntp.dca1.giganews.com!nntp.giganews.com!l13no113345iga.0!news-out.google.com!k20ni2qgd.0!nntp.google.com!z60no434588qgd.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Fri, 3 Apr 2015 02:46:51 -0700 (PDT) In-Reply-To: <17k4cw97n2vry.1de70j504frlo.dlg@40tude.net> Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=212.99.10.162; posting-account=ku4DIwoAAACRt0A2H-srh5aOk_YodLAH NNTP-Posting-Host: 212.99.10.162 References: <59ac455c-72f6-43e2-8a79-efc0f3e16d9a@googlegroups.com> <19qfgu5pjszm5.s5y5u8r0zx8k.dlg@40tude.net> <161a69af-a392-4214-bd92-0e20e7522cca@googlegroups.com> <1ht5q4lxmtf3p.mntbczbpti5n.dlg@40tude.net> <0ac76a41-d276-47d4-8659-530229802d12@googlegroups.com> <1ieaan02ff638.n6kjnn72tsp3$.dlg@40tude.net> <1o9qidr7413f4$.1jbc41w6r9j62.dlg@40tude.net> <1q1hq0qt8n15$.kxfdpvio0p1w.dlg@40tude.net> <7ec7c26a-fa55-4ae4-a6c5-b117e2ca3836@googlegroups.com> <17k4cw97n2vry.1de70j504frlo.dlg@40tude.net> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <8b8959de-2fe6-4108-9044-e4e19fac432b@googlegroups.com> Subject: Re: Languages don't matter. A mathematical refutation From: =?ISO-8859-1?Q?Jean_Fran=E7ois_Martinez?= Injection-Date: Fri, 03 Apr 2015 09:46:51 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Xref: number.nntp.giganews.com comp.lang.ada:192700 Date: 2015-04-03T02:46:51-07:00 List-Id: On Thursday, April 2, 2015 at 6:39:11 PM UTC+2, Dmitry A. Kazakov wrote: > On Thu, 2 Apr 2015 08:58:41 -0700 (PDT), Jean Fran=E7ois Martinez wrote: >=20 > > On Thursday, April 2, 2015 at 3:36:02 PM UTC+2, Dmitry A. Kazakov wrote= : > >=20 > >>> To change the subject a bit, is there any possibility of using > >>> the probabilistic approach to estimating the long-term cost of > >>> maintenance given a history of errors with a particular language? > >>=20 > >> I don't think so. Errors do not occur, they are present or introduced.= The > >> only probabilistic model could be random selection of a given error fr= om > >> the pool of errors. This is not related to the language choice. All > >> difference here is in the pools, since errors made in C are different = from > >> errors made in Ada. You change the language, you get *other* errors, n= o > >> statistics across to compare. > >=20 > > Really? Errors occur because of progarmmer quality, physical shape (ha= d a > > bad night), distracting events, use of alcohol and drugs and plenty, > > plenty of factors. One of them being that a bird has just landed in > > front of your window. Random. =20 >=20 > You are describing the process of programming. This is another model, whi= ch > is certainly not random. If that were random, the same programmer asked t= o > design the same program several times would randomly introduce any possib= le > errors. That is not the case. People have memory, they learn, decision > making process is nowhere random. In general, only typo errors could be > considered random. Anything above simple motoric functions is not random. > =20 > --=20 > Regards, > Dmitry A. Kazakov > http://www.dmitry-kazakov.de The problem is: None of what you have said from the beginning is relevant about how statitical tests work. Let's say we have white balls and black balls. The reasons they are white = or black is definitely not random since it depends on the operator filling = the machine with white or black paint. :-). Then from a conceptually infi= nite-sized urn you take two samples at random. The averages of the sample= s will differ from one another and from the expected value http://en.wikipe= dia.org/wiki/Expected_value (that is the propoortion of white balls in our = urn) but usually not by that much and anyway you can calculate probability = of the difference and probability of difference being above a certain thres= hold. More exactly we approximate to a Student law or to a gaussian law d= epending on the size of the sample. =20 Now we have two samples of programmers and in each sample there are white = balls (programmers who succeeded) and black balls (programmers who failed).= =20 Just like for balls being black or white due to deterministic reasons, they may succeed or fail for deterministic reasons We don't care and = don't care why. We make the hypothesis these are samples= of the same urn (ie from an homogeneous population so same proportion of w= hite and black balls, of succeeding and failing programmers) calculate the = averages and the probability we would have of getting a such difference or = higher. Then we compare that probability with a threshold (usually 5% or 1%= ) and if it is superior we accept the hypothesis (two samples from the same= urn) if it is inferior we reject the hypothesis and assumme these are not two samples = from the same urn but from different urns with one of them having a higher = mix of white balls (succeeding programers). In our case probability was in= ferior to one in one million so the null hypothesis (same urn) is rejected. That is math, it is correctly applied and that is all what we can = deduce with math. To find the reasons of why one urn that happens to be la= belled Ada has a higher proportion of white balls than the urn labelled C requires applying field knowledge.=20 Regards Jean-Fran=E7ois Martinez