【#GRE留开云kaiyun(中国)外语考试# #2019年GRE数开云kaiyun(中国)考点：Conditional#】世上的事，只要肯用心去开云kaiyun(中国)，没有一件是太晚的。你只要记住你的今天比昨天进步了一点，那么你离你的梦想也就更近了一步。©开云网页版整理了“2019年GRE数开云kaiyun(中国)考点：Conditional”，欢迎阅读参考！更多相关讯息请关注©开云网页版！
Conditional
Probability of event A conditioned on the fact that event B has happened is
called the conditional probability and written as P(AIB).
P(AIB)=Probability Both A and B happens/ Probability B happens.
Example:
A six-sided die with faces from 1 to 6 is rolled twice. What is the
probability that the face 5 turned up on first try given that the sum of the two
faces is 9?
P(sum of faces is 9)=4/36=1/9.
P(face 5 turns up on the first try and sum is 9)=(1/6)*(1/6)=1/36.
P(face 5 turned up on first try given sum is 9)=(1/36)*(1/9)=1/4
Remember:
If P(AIB)=P(A),then two events A and B are independent, that is occurrence
of one does not influence the other
