5-24 今天看OG关于Discrete Probability时,有个地方一直没想明白,又哪位高人能帮忙解答一下。问题如下: Events A, B and C for which P(A)=0.23, P(B)=0.40, P(C)=0.85. Events A and B are mutually exclusive and events B and C are independent. One can deduce that P(A and C)≦P(A)=0.23, since A ∩ C is a subset of A, and P(A and C)≦P(C)=0.85 since C is a subset of A∪C. Thus, one can conclude that 0.85≦P (A or C) ≦1 and 0.85≦P(A or C) ≦0.23 这是OG11 P120给的解释,其中有连个地方不太明白: 1、 用since C is a subset of A∪C来解释 P(A and C)≦P(C)=0.85,是不是有问题,因为A and C= A ∩ C,所以P(A and C)≦P(C)=0.85的解释应该是A ∩ C is a subset of C。 2、 0.85≦P (A or C) ≦1 and 0.85≦P(A or C) ≦0.23是怎么推出来的? |