[R] Coin Toss Simulation

[Dimitris Rizopoulos]

try this:

n <- 3
data.frame(Exp = seq_len(n),
     Heads = rbinom(n, 200, 0.5))


I hope it helps.

Best,
Dimitris


On 10/13/2010 7:28 PM, Shiv wrote:
>
> I am trying a simple toin coss simulation, of say 200 coin tosses. The idea
> is to have a data frame like so:
>      Experiment#    Number_Of_Heads
>       1                   104
>       2                    96
>       3                    101
>
> So I do:
>
>   d<-data.frame(exp_num=c(1,2,3));  /* Just 3 experiments to begin with */
>   d$head_ct<-sum(sample(0:1,200,repl=TRUE));
>   d;
>    exp_num    head_ct
> 1       1        85
> 2       2        85
> 3       3        85                             /* the same scalar value is
> applied to all the rows */
>
> So I tried using "within", and "for", and making the "sum(   " as a
> function, and I end up with the same...I get the same constant value.  But
> what I want of course is different "samples"....
>
>
>

-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

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