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已知P(A非)=0.3,P(B)=0.4,P(AB非)=0.5,求条件概率P...

p(b)=0.4,p(ab)=0.5,题目错了!p(b/aub非)=p(b(aub非))/p(aub非) p(aub非)=p(a)+p(b非)-p(ab非)=0.7+0.6-0.5=0.8 p(b(aub非))=p(ab)=p(a-ab非)=p(a)-p(ab非)=0.7-0.5=0.2 p(b/aub非)=p(b(aub非))/p(aub非)=0.2/0.8=1/4

p(非(ab))=1-p(ab)=0.8 即p(ab)=0.2 p(au非b)=p(a)+p(非b)-p(a非b)=p(a)+p(非b)-[p(a)-p(ab)]=0.7+(1-0.4)-(0.7-0.2)=0.8 p(a∩(a非b))=p(a)-p(ab)=0.7-0.2=0.5 ∴ p(a|au非b)=p(a∩(a非b))/p(au非b)=0.5/0.8=5/8

<p>P(B|AUB)=P(b,AUB)/p(AUB)=p(b)/p(AUB)</p><p>P(AUB)=p(a)+p(b)-p(ab) </p><p>p(a)=p(ab)+p(AB非) 0,7=p(ab)+0,5 p(ab)=0,2</p> <p> </p> <p>2 P(AUB)=p(a)+p(b)-p(ab) =0,7+0,4-0,2=0,9</p> <p>1 p(b)/p(AUB)=0,4/0,9=4/9</p>

P(B)=0.4,可得P(B拔)=0.6P(AB拔)=0.5P(A拔)=0.3,可得P(A)=0.7P(A+B拔)=P(A)+P(B拔)-P(AB拔)=0.7+0.6-0.5=0.8P(B(A+B拔))=P(AB)=P(A)-P(AB拔)=0.7-0.5=0.2P(B|A+B拔)=P(B(A+B拔))/P(A+B拔)=1/4

P(~A)=0.3 P(B)=0.4 P(A~B)=0.5 P(B|AU~B)=P(A,AU~B)/P(AU~B) =P(AB)/(1-(P(B)-P(AB)) P(AB)=P(A)-P(A~B)=0.2 所以 原式=0.2/0.8=1/4

P(B)=0.4,可得P(B拔)=0.6 P(AB拔)=0.5 P(A拔)=0.3,可得P(A)=0.7 P(A+B拔)=P(A)+P(B拔)-P(AB拔)=0.7+0.6-0.5=0.8 P(B(A+B拔))=P(AB)=P(A)-P(AB拔)=0.7-0.5=0.2 P(B|A+B拔)=P(B(A+B拔))/P(A+B拔)=1/4

p(~a)=0.3p(b)=0.4p(a~b)=0.5p(b|au~b)=p(a,au~b)/p(au~b)=p(ab)/[1-(p(b)-p(ab)]p(ab)=p(a)-p(a~b)=0.2∴p(b|au~b)=0.25

p(a+b)=p(a)+p(b)-p(ab)=0.3 p(ab)=p(a)+p(b)-0.3=0.9-0.3 =0.6 p(a\b)=p(ab)\p(b)=0.6\0.4 =1.5?确定题目没错吗?思路是这样,但是概率怎么大于1了

解答:P(A∩B)=P(A)-P(A∩非B)=1-0.3-0.5=0.2 ∵P(非A∩B)=P(B)-P(A∩B)=0.4-0.2=0.2 ∴P(AU非B)=1-P(非A∩B)=0.8 ∴P(B|A并非B)=P((AU非B)∩B)/P(A并非B)=P(A∩B)/P(AU非B)=0.2/0.8=0.25 如果满意记得采纳哦!你的好评是我前进的动力.(*^__^*) 嘻嘻…… 我在沙漠中喝着可口可乐,唱着卡拉ok,骑着狮子赶着蚂蚁,手中拿着键盘为你答题!!!

P(AUB) =P(A)+P(B) -P(A∩B) = 0.7+0.5-0.4 =0.8 P(A|AUB) = P(A∩(AUB))/P(AUB) =P(A)/P(AUB) =0.7/0.8 =7/8

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