Identifier: p1collectedpaper07list (find matches)
Title: Collected papers
Year: 1904 (1900s)
Authors: Lister Institute of Preventive Medicine, London
Subjects: Medicine
Publisher: London
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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ph 7. 522 On the Distribution of the Means of Samples accordingly present features of interest quite apart from the particular case ofthe opsonic index. These remarks apply with special force to medical statisticswhich so frequently involve the use of ratios or indices. The importance of the problem tempted us to devote some little time to atheoretical consideration of the subject and we arrived at a few analytical resultswhich might, we thought, be of some value. It is, however, unnecessary forus to publish these incomplete investigations, since Professor Karl Pearson hassucceeded in obtaining a full solution of the problem*. We therefore confineourselves to an empirical solution which is sufficient for our immediate object. 140r 130 - 120 - 100 -■ 90*- 80 70 - 60 60- 30 f- 20 - to -^=i 3 ^4 ^5 ^8 ^7 ^8 ^ 10 Il I EE3. 2 1-3 1-4 1-5 16 1-7 18 1-9 20 2-1 2 2 Opsonic Index.Graph 6. Curve of 258 secondary without replacement. See the following paper. M. Greenwood and J. T). C White 2:\
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Houdnhdd^ 524 On the Distribittion of the Means of Samples i The actual number of bacteria in each sample of 25, 50 or 100 cells was copiedout on a separate slip of cardboard, so that we had 800, 400 and 200 cardscorresponding to the samples of 25, 50 and 100 cells. The cards used were smallpieces of correspondence cards which, being smooth, could be shuffled very easily. With these cards the following experiments were performed. Taking the caseof the 400 cards relating to the fifties, the cards were thoroughly shuffled and onedrawn out. The number on the card was written down, the card not beingreplaced. The remainder were once more shuffled, another drawing was made andthe process was repeated until the whole 400 had been drawn. The cards werethen once more shuffled and the process repeated, the second set of numbers beingwritten down one by one under the first set of values. Each number of the firstset was then divided by the corresponding number in the second set and the 400 65 -

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