20/06/29 01:15:22.41 ASlt7m8R.net
>>774
> # Rが使えるなら
> n=1000
> p=0.001
> x=0:1000
> # (1)
> pbinom(2,n,p)
[1] 0.91979065715979891
> #(2)
> sum(x*dbinom(x,n,p)/sum(dbinom(x,n,p)))
[1] 1
> #(3)
> ppois(2,1)
[1] 0.91969860292860584
20/06/29 01:15:22.41 ASlt7m8R.net
>>774
> # Rが使えるなら
> n=1000
> p=0.001
> x=0:1000
> # (1)
> pbinom(2,n,p)
[1] 0.91979065715979891
> #(2)
> sum(x*dbinom(x,n,p)/sum(dbinom(x,n,p)))
[1] 1
> #(3)
> ppois(2,1)
[1] 0.91969860292860584