The Doctrine of Chances: Or, a Method of Calculating the Probabilities of Events in Play. The Third Edition, Fuller, Clearer, and More Correct Than the Former. By A. de Moivre, ...

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A. Millar, 1756 - 348 pages
 

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Page 226 - The sum of the products of the roots taken two and two, with their respective signs, is equal to the co-efficient of the third term.
Page xi - The Author of this Work, by the failure of his Eye-sight in extreme old age, was obliged to entrust the Care of a new Edition of it to one of his Friends; to whom he gave a Copy of the former, with some marginal Corrections and Additions, in his own hand writing.
Page 209 - Terms next following as have been taken already, but prefix to them in an inverted order, the Coefficients of the preceding Terms. But if d be an even number, take so many Terms of the said Power as there are Units in...
Page 1 - Wherefore, if we constitute a fraction whereof the numerator be the number of chances whereby an event may happen, and the denominator the number of all the chances whereby it may either happen or fail, that fraction will be a proper designation of the probability of happening.
Page 4 - ... it is the product of the sum adventured, multiplied by the loss. What is called advantage or disadvantage in play, results from the combination of the several expectations of the gamesters, and of their several risks. Thus, supposing A and B play together, and that A has deposited 51. and B 31., and that the number of chances which A has to win is 4, and the number of chances B has to win 2, and that it were required to determine the advantage or disadvantage of the players, we may reason thus...
Page 263 - Rules that might eafily be applied to the Valuation of feveral Lives; which, however, was happily overcome, the Rules being fo eafy, that by the Help of them, more can be performed in a Quarter of an Hour, than by any Method before extant , in a Quarter of a Tear.
Page 38 - ... and the product 3'5 will show that there is more than an equality of chance in four tickets for one or more prizes, but less than an equality in three. REMARKS. In a lottery whereof the blanks are to the prizes as 39 to 1, if the number of tickets in all were but 40, the proportion above mentioned would be altered, for 20 tickets would be a sufficient number for the just expectation of a single prize. Again, if the number of tickets in all were 80, still preserving the proportion of 39 blanks...
Page 251 - As, upon the Supposition of a certain determinate Law according to which any Event is to happen, we demonstrate that the Ratio of Happenings will continually approach to that Law, as the Experiments or Observations are multiplied : so, conversely, if from numberless Observations we find the Ratio of the Events to converge to a determinate quantity, as to the Ratio of P to Q,', then we conclude that this Ratio expresses the determinate Law according to which the Event is to happen.
Page 263 - Tears; it appears, that Life is carried to 90, 95, and even to 100 Years ; I am no more moved by it, than by the Examples of Parr or Jenkins, the firft of whom lived 152 Tears, and the other 167.
Page 252 - Events would converge to no fixt Ratio at all. Again, as it is thus demonstrable that there are, in the constitution of things, certain Laws according to which Events happen, it is no less evident from Observation, that those Laws serve to wise, useful and beneficent purposes; to preserve the stedfast...

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