A number of trials in which the probability of success varies from trial to trial. Let be the number of successes, then
(1)
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where is the variance of and . Uspensky has shown that
(2)
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where
(3)
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(4)
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(5)
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(6)
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and . The probability that the number of successes is at least is given by
(7)
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Uspensky gives the true probability that there are at least successes in trials as
(8)
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where
(9)
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(10)
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