Re: 不知統計可以在這裡問嗎?徵統計解答
※ 引述《friedman911 (小咪)》之銘言：
某一工廠,生產的產品當中有15%為不良品,A從中抽出20件出來,問:
a:本題的隨機變數應如何設定?
[sol]
P{X = i} = (C20取i) * (0.15)^i * (0.85)^(20 - i) i = 0,1,...,19,20
b:機率分配如何?
[sol]
Binomial distribution with (n,p) = (20,0.15)
n represents number of products
p represents the probability of fail products
c:抽出不良品中,有3件為不良品的機率有多大?
[sol]
By a,let i = 3
d:求變異數,期望值
[sol]
Expected value = n * p = 20 * 0.15 = 3
Variance = n * p * (1 - p) = 2.55
請求各位大大解答!
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