2013年4月新gre考試:gre數(shù)學沖刺要點之Conditional

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    新gre數(shù)學的難度相當于高中數(shù)學水平,只要大家認真復習,在新gre數(shù)學考試中拿高分甚至拿滿分都是很有可能的。不過大家也不能忽略新gre數(shù)學中可能會出現(xiàn)的考點難點。下面,就為大家整理新GRE數(shù)學復習要點:Conditional,希望對大家有所幫助。
    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
    應對gre數(shù)學考試的時候,考生不要過于緊張,把基本概念弄明白,再記住一些新版gre數(shù)學必備的詞匯,那么相信新版gre數(shù)學應該沒有問題。