# [R] Hi, Coding problem

Uwe Ligges ligges at statistik.tu-dortmund.de
Thu Feb 26 09:54:15 CET 2009

```
Ssophia wrote:
>
>   Hi, there
>
>
>
>   Below is my code to one Homework question. I couldn't come up with the reasonable answer.
^^^^^^^^

>     thank you
>
>
>     Question is Coding P{X=j} =(1/2)^(j+1) + (1/2) *2^(j-1)/3^j
>     my code is
>     sim <- function(n.gen){
>     urandom <- runif(n.gen)
>     sim.vector <- rep(0,n.gen)
>     for(j in 1:n.gen){
>      i <- 1
>      p <- 5/12
>      F <- p
>      while(urandom[j] >= F){
>       p <- p*((1/2)^(i+1)+1/3*(2/3)^i)/((1/2)^i+(1/2)*(2/3)^i)
>       F <- F+p
>       i<-i+1
>       }
>      sim.vector[j] <- i
>     }
>     # output
>     sim.vector
>     }
>
>
>
>     result is
>
>        1    2    3    4    5    6    7    8   11
>     0.37 0.22 0.16 0.13 0.05 0.02 0.03 0.01 0.01
>
>
>
>     always, there are some numbers missing, it should be continuous.
>
>     why 9 and 10 are missing
>
>     thank you
>
>
>
>     sophia
>
>
>
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