问题标题：
概率论问题Supposethatwhenamachineisadjustedproperly,50%oftheitemsproducedbyitareofhighqualityandtheother50%areofmediumquality.Suppose,however,thatthemachineisimproperlyadjustedduring10%ofthetimeandthat,u
问题描述：
概率论问题
Supposethatwhenamachineisadjustedproperly,50%oftheitemsproducedbyitareofhighqualityandtheother50%areofmediumquality.Suppose,however,thatthemachineisimproperlyadjustedduring10%ofthetimeandthat,undertheseconditions,25%oftheitemsproducedbyifareofhighqualityand75%areofmediumquality.
Supposethatfiveitemsproducedbythemachineatacertaintimeareselectedatrandomandinspected.Iffouroftheseitemsareofhighqualityandoneitemisofmediumquality.What'stheprobabilitythatthemachinewasadjustedproperlyatthattime?
应该怎么做呢?
傅山回答：
这个就是贝叶斯公式的应用.设X表示5个产品中优良的个数.取0-5Y表示是否调整好.1表示调整好.0表示没调整好.那么问题就是求P（Y=1/X=4）问题知道了.就需要计算P（X=4）与P（Y=1,X=4）还有P（Y=1）P（X=4）用全概率公式...
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