A-level数学备考知识点:二项式分布!

A-level的备考过程中,以知识点为单位进行归类不失为一种非常高效的学习方法,通过进行区块的系统整理,更容易建立知识点之间的联系,增强对题型的理解,应对综合性的大题。

首先我们要能够判定出题干给出的信息是否满足二项式分布,以下为二项式分布条件:

Ex:The probability of a spinner landing on red is , For 12 spins, find the probability:

A. There are no more than 2 reds;

B. There are at least 5 reds.

解析:首先我们先判定这是否满足二项式分布,fixed number of trial=12, two possible outcomes,which is land on red/ not red, fixed probability of success=, the trials are independent of each other. 四项都满足,就可以通过查表求的。

Let X be the number of red in spins.

X~B( 12, )  P(X=k)=12CₖPᵏ(1-P)¹²-ᵏ   ,P(X≦2)查表可得:

接下来,我们一起来看一道真题:

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