Das Durchschnitts-Verhältniss 2 : 1 erscheint demnach als gesichert.
The average proportion of 2 : 1 thus seems to be ascertained.
That Mendel had this sentence printed with spaced letters indicates that he considered the results obtained from his experiments on F2-plants with dominant traits to be highly significant. In a classic paper, R. A. Fisher demonstrated, however, that Mendel misconstrued his expectation of a 2 : 1 ratio. Since he tested for homozygosity by growing ten offspring only, there remained a significant chance that in “between 5 and 6 percent” of cases all ten offspring show the dominant trait although their parent is heterozygous. That the results of Mendel’s experiments nevertheless accorded well with his expectations shows, according to Fisher, “that sampling errors in this case caused a deviation in the right direction, and of almost exactly the right magnitude, to compensate for the error in theory” (Ronald A. Fisher, “Has Mendel’s Work Been Rediscovered?”, Annals of Science, 1, 1936, pp. 115–137, here p. 125). This gave rise to a long-standing debate about whether Mendel’s results “were to good to be true”; see Allan Franklin, A. W. F. Edwards, Daniel J. Fairbanks, and Daniel L. Hartl, Ending the Mendel-Fisher Controversy (Pittsbrugh: University of Pittsburgh Press, 2008).
That Mendel had this sentence printed with spaced letters indicates that he considered the results obtained from his experiments on F2-plants with dominant traits to be highly significant. In a classic paper, R. A. Fisher demonstrated, however, that Mendel misconstrued his expectation of a 2 : 1 ratio. Since he tested for homozygosity by growing ten offspring only, there remained a significant chance that in “between 5 and 6 percent” of cases all ten offspring show the dominant trait although their parent is heterozygous. That the results of Mendel’s experiments nevertheless accorded well with his expectations shows, according to Fisher, “that sampling errors in this case caused a deviation in the right direction, and of almost exactly the right magnitude, to compensate for the error in theory” (Ronald A. Fisher, “Has Mendel’s Work Been Rediscovered?”, Annals of Science, 1, 1936, pp. 115–137, here p. 125). This gave rise to a long-standing debate about whether Mendel’s results “were to good to be true”; see Allan Franklin, A. W. F. Edwards, Daniel J. Fairbanks, and Daniel L. Hartl, Ending the Mendel-Fisher Controversy (Pittsbrugh: University of Pittsburgh Press, 2008).
proportion = Verhältniss See p. 3, s. 8.