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1 Studies in the History of Statistics and Probability ... - Sheynin, Oscar

1 Studies in the History of Statistics and Probability ... - Sheynin, Oscar

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obta<strong>in</strong><strong>in</strong>g a deviation from <strong>the</strong> <strong>the</strong>ory assumed to be valid, scientistshave been attempt<strong>in</strong>g to calculate, if possible, <strong>the</strong> probability <strong>of</strong> adeviation not less than that. If that probability was high, 1/2, say,everyth<strong>in</strong>g was <strong>in</strong> order; o<strong>the</strong>rwise, suppos<strong>in</strong>g that its order was1/1000, it was advisable to look for <strong>the</strong> cause <strong>of</strong> <strong>the</strong> deviation. If,f<strong>in</strong>ally, it was moderate, its order be<strong>in</strong>g 1/10, say, <strong>the</strong> case wasdoubtful <strong>and</strong> a f<strong>in</strong>al decision impossible. Can we object to such k<strong>in</strong>d <strong>of</strong>apply<strong>in</strong>g <strong>the</strong> confidence level?I do not underst<strong>and</strong> Alimov’s concept <strong>of</strong> <strong>in</strong>dependence ei<strong>the</strong>r. On p.80 he th<strong>in</strong>ks that secondary trials, that is, data on <strong>the</strong> assortment <strong>of</strong><strong>in</strong>dications <strong>in</strong> different families, unconnected with each o<strong>the</strong>r, can bestatistically dependent. But how could that occur with <strong>the</strong> outcomes <strong>of</strong>different trials unconnected with each o<strong>the</strong>r? If as a result <strong>of</strong> one trialevents A <strong>and</strong> B can ei<strong>the</strong>r happen or fail, <strong>the</strong>y can be statisticallydependent <strong>and</strong>, when treat<strong>in</strong>g this dependence accord<strong>in</strong>g to Mises, weshould use a s<strong>in</strong>gle record. But <strong>in</strong> case <strong>of</strong> two absolutely different trialswe should apparently <strong>in</strong>troduce someth<strong>in</strong>g like a direct product <strong>of</strong> tworecords.F<strong>in</strong>ally, concern<strong>in</strong>g my treatment <strong>of</strong> En<strong>in</strong>’s data, Alimov remarksfirst <strong>of</strong> all that his number <strong>of</strong> families is so small (11 + 14 = 25), that<strong>the</strong>ir treatment did not warrant <strong>the</strong> waste <strong>of</strong> ei<strong>the</strong>r time or paper with aspecial non-l<strong>in</strong>ear scale. I will answer that by stat<strong>in</strong>g that, on <strong>the</strong>contrary, I aimed at show<strong>in</strong>g that <strong>the</strong> image <strong>of</strong> a distribution functionunlike that <strong>of</strong> a histogram allows to obta<strong>in</strong> sensible results even whenhav<strong>in</strong>g such a small sample size.Then, Alimov states that it was possible to arrive at my conclusionsby compil<strong>in</strong>g an extended sample 1 . To some extent this is correct, butto some extent wrong. After tak<strong>in</strong>g samples <strong>of</strong> about <strong>the</strong> same size, <strong>the</strong>frequencies <strong>in</strong> En<strong>in</strong>’s second sample will be closer to <strong>the</strong> <strong>the</strong>oreticalmagnitudes than Ermolaeva’s similar frequencies. This is seen <strong>in</strong>Alimov’s table (1978, p. 78). It can be <strong>the</strong>refore concluded, ifErmolaeva’s data are considered as a st<strong>and</strong>ard, that <strong>the</strong>re is sometrouble with En<strong>in</strong>’s materials.However, after calculat<strong>in</strong>g <strong>the</strong> chi-squared statistic (Tutubal<strong>in</strong> [iii]),a st<strong>and</strong>ard is not needed. Actually, Alimov (1978, pp. 80 – 81)believes that En<strong>in</strong>’s data should be treated not by means <strong>of</strong> <strong>the</strong> normaldistribution <strong>of</strong> <strong>the</strong> normed frequencies, but by a more subtle model. Inpr<strong>in</strong>ciple, I completely agree, only that model should not be a mixture<strong>of</strong> b<strong>in</strong>omial distributions (Alimov, p. 80, formula (21)), but it shoulddirectly consider <strong>the</strong> actual numerical strength <strong>of</strong> <strong>the</strong> families. A series<strong>of</strong> b<strong>in</strong>omial trials would be obta<strong>in</strong>ed hav<strong>in</strong>g a known number <strong>of</strong> trials<strong>and</strong> a known probability <strong>of</strong> success. Underst<strong>and</strong>ably, such a model isbarely convenient <strong>and</strong> <strong>the</strong>refore <strong>the</strong> stupidest Monte Carlo method 2will apparently be most effective for calculat<strong>in</strong>g <strong>the</strong> various pert<strong>in</strong>entprobabilities. Thus, for example, <strong>the</strong> true distribution <strong>of</strong> <strong>the</strong>Kolmogorov statistic or some o<strong>the</strong>r statistic measur<strong>in</strong>g <strong>the</strong> deviationfrom <strong>the</strong> Mendelian law can be determ<strong>in</strong>ed. S<strong>in</strong>ce such statistics arera<strong>the</strong>r diverse, we conclude that not only <strong>the</strong> electron or <strong>the</strong> atom butalso <strong>the</strong> certa<strong>in</strong>ly carelessly constructed Ermolaeva’s tables are<strong>in</strong>exhaustible 3 .137

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