Example:
扔硬币8次,7次为头(1)的概率?
······································································(1.1)
···························································································(1.2)
所以由(1.1),(1.2) 得 其 p=
那在R怎么算呢??
可以直接自己输入计算
> choose(8,7)*0.5^8+choose(8,8)*0.5^8
[1] 0.03515625
又或者利用pbinomm来实现:
> pbinom(6,size=8,prob = 0.5,lower.tail = F)
[1] 0.03515625