Lectures on state medicine delivered before the Society of Apothecaries at their hall in Blackfriars May & June 1875 / by F. S. B. François de Chaumont.

  • de Chaumont, F. S. B. François.
Date:
1875
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on state medicine delivered before the Society of Apothecaries at their hall in Blackfriars May & June 1875 / by F. S. B. François de Chaumont. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    Table XXIII. Poisson's Formula. /2.m.n. V ~fP Where = total number of events. „ m— „ of po.sitive events. ,, n= ,, of negative events. Or it may be stated thus : A /8-p(g-p) 2 ~ V r/ Where q = total number of events. ,, p = ,, „ in a particular direction. For mean erroi'. 1. Find the mean of the series of observations; find the mean of all the observations above the mean, and subtract the mean from it: this gives the mean error in excess. 2. Find the mean of all the observations below the mean, and subtract it from the mean: this gives the mean error in deficiency. Add the two quantities and take the half: this is the mean error. For error of mean square. Find the sum of the squares of apparent errors : this is done by taking the sum of the squares of the observations and sub- tracting from it the square of the mean multiplied by the num- ber of observations : then calling this result S we have being the number of observations) :— Error of mean square of a single measure of the result -V.5 /~8~ ?i(«—1) For probable error. Multiply the error of mean square by 0‘6745. (See Airy’s ‘Theory of Errors of Observation;’ Kohlrausch’s ‘ Physical Measurements; ’ and other works.)