[R] Vectors, Loops, Rnorm and KS-Testing

Ivan Calandra ivan.calandra at univ-reims.fr
Mon May 23 16:56:03 CEST 2016


Hi Nicoletta,

You need to read more introductory material.
One of the problems with your code is that you actually don't create any 
value, let alone any vector; you just display it with cat().
Then you try to create each value of your vector with an explicit for 
loop, but you don't need to; replicate() does the job in a compact code.

So if I understand correctly what you want to achieve, I would do this:
kolmo <- function(x, meanR=0, sdR=1, repet=1){
     out <- replicate(repet, mean(rnorm(x, meanR, sdR)))
     return(out)
}
# I changed the names of your arguments to make it less confusing (but I 
wasn't imaginative)
# I set some default values for 'meanR' and 'sdR', which are actually 
the defaults of rnorm()
# 'return(out)' is not necessary but I prefer to explicitly write what I 
want the function to output

Example:
kolmo(x=10, repet=3)

HTH,
Ivan

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Ivan Calandra, PhD
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Le 23/05/2016 à 11:30, Nicoletta Sabov a écrit :
> Hi there,
>
> I need a function, that calculates the mean of a desired amount of normally distributed numbers and repeats this process for a desired number of repetitions. The function should return only a single vector consisting solely of the calculated means. Also the user of this function must be able to specify the parameters of the normal distribution used while calculating the means. I need this function for the Kolmogorov Smirnov Test.
> I am a total beginner, so far I only have come to this point:
>
> kolmo <- function(x, mean, sd, rep){
>    
>    for(i in rep){
>      cat(mean(rnorm(x, mean, sd)))
>      
> }}
> This returns a simple number, but I do need a vector to be returned.
> Thanks a lot in advance!
>
>
>
> 	[[alternative HTML version deleted]]
>
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