本文为大家介绍的GRE数学复习考点是“conditional”。

新版GRE数学复习重要考点：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.

以上的内容大家一定要好好掌握，在考试的时候发挥出自己应有的水平。