elberlin asked in 科學數學 · 7 years ago

統計學的一個題目(急) binomial distribut

題目:

binomial distribution has parameters n=100 and p=0.5 Using the normal approximation to the binomial distribution what is the probability that the number of successes is more than 60 ?

小弟研究了很久,都無法順利解出

我的算法如下..

P(X>60)

=1-P(X<=60)

1-(1/2)^100 x SUM(i=0~60) C(100取x)

就解不下去了..

1 Answer

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    In using normal approximation to binomial distribution, the continuity correction of 0.5 should be used, therefore:

    With μ = 50 and σ = 5, the required probability should be:

    P(X >= 60.5) for "more than 60", which is equivalent to:

    P[z >= (60.5 - 50)/5] = P(z >= 2.1)

    = 0.0179

    Source(s): 原創答案
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