作者ntnulcy (要活就要Don't)
看板Statistics
标题[问题] 一题机率
时间Wed Jul 25 00:08:54 2007
At a grocery stone, eggs come in cartons that hold a dozen eggs. Experience
indicates that 78.5% of the cartons have no broken eggs, 19.2% have one
broken eggs, 2.2% have two broken eggs, 0.1% have three broken eggs, and
that the percentage of cartons with four or more broken eggs is negligible.
An egg selected at random from a carton is found to be broken. What is
the probability that this egg is the only broken one in the carton?
我的想法是......
P(A1)：没有蛋破掉的机率：0.785
P(A2)：一个蛋破掉的机率：0.192
P(A3)：两个蛋破掉的机率：0.022
P(A4)：三个蛋破掉的机率：0.001
P(A5)：拿一个蛋出来的事件机率：1/12
P(A5 ∩ A2) P(A5) P(A2│A5)
所求 = P(A5│A2) = ─────── = ─────────
P(A2) P(A2)
1/12 ‧ 0.192
= ──────── = 1/12
0.192
不知道这样做对不对？
恳请达人赐教 Orz
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1F：推 bcs:满好用的，先安装np++,再下载download，把dowlonad的东西全 07/25 13:07
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