[R] Simulation of data

2008-10-20 Thread Marcioestat 

Hi listers,
I am working on a program of statistical analysis of simulated data and I've
been searching the error at the program, but I didn't find it!
It is something about the WHILE procedure, the error says: Error in while
(ecart >= d) { : missing value where TRUE/FALSE needed
Thanks in advance!
Márcio

k<-100
d<-0.00112
z<-rnorm(100, 0, 1)
prop<-rep(0,100)
for (i in 1:100){
if (z[i]>1.75){
prop[i]<-1}
else{prop[i]<-0}}
proportion<-mean(prop)
ecart<-sqrt((proportion*(1-proportion))/k)
while(ecart>=d){
prop_<-0
w<- rnorm(1, 0, 1)
z<-c(z,w)
{if (w>1.75){
prop_<-1}
else{
prop_<-0}
}
prop<-c(prop, prop_)
proportion<-proportion+(prop[k+1]-proportion/(k+1))
ecart<-sqrt((proportion*(1-proportion))/(k+1))
k<-k+1
}

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Re: [R] Simulation of data

2008-10-21 Thread Marcioestat 

Hi Barry,
As you explained I find out my mistake... I wasn't supposed to use a
recursive formula!
So, what I needed, it's just to use the proportion by the function mean to
reach my results...
Thanks,
Márcio


Barry Rowlingson wrote:
> 
> 2008/10/21 Marcioestat <[EMAIL PROTECTED]>:
>>
>> Hi listers,
>> I am working on a program of statistical analysis of simulated data and
>> I've
>> been searching the error at the program, but I didn't find it!
>> It is something about the WHILE procedure, the error says: Error in while
>> (ecart >= d) { : missing value where TRUE/FALSE needed
> 
>  How much do you know about debugging programs? Read the R help for
> "debug" and "browser". These tools let you inspect your program at any
> point so you can see what the values of variables are.
> 
>  Anyway, for you error message, I'd guess there was a missing value in
> 'ecart' or 'd' or both:
> 
>  > ecart
>  [1] NaN
>  > d
>  [1] 0.00112
> 
>  so, ecart is Not A Number. How could that happen? Well, ecart is a
> square root of something, so maybe that something is negative:
> 
>  > proportion*(1-proportion)
> [1] -0.01874365
> 
>  Hmmm
> 
>  > proportion
>  [1] 1.018405
> 
>  I would bet that proportion isn't supposed to be more than 1 (or less
> than 0). How did that happen?
> 
>  This line looks a bit dodgy:
> 
>   proportion<-proportion+(prop[k+1]-proportion/(k+1))
> 
> since you're adding something to a proportion... Should that division
> be outside the parentheses? Hard to tell without knowing exactly what
> the code is trying to do. The proportion goes >1 when w is over your
> 1.75 threshold. Are you just trying to update proportion=mean(prop)
> again? Why not do that? If I replace your line with proportion =
> mean(prop) then it runs and terminates after about 32000 iterations.
> 
>  Protip: Updating a mean like this is probably quicker but if you ever
> write a tricky bit of code test it first!
> 
> Barry
> 
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> PLEASE do read the posting guide
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> 
> 

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[R] Bootstrap

2008-10-21 Thread Marcioestat 

Hi listers,
I've been work on a bootstrap estimator and I don't know how to make a
certain manipulation at the data.
As an example I have the following data and samples... I need now to
identify the vector in wich I sampled the id, I mean that I have to merge
the files having the key as the id of the samples in order to find the
vector that were selected.
Thanks in advance,
Márcio

id<-seq(1:49)
x<-runif(49)
u<-runif(49)
data<-cbind(id,x,u)
B<-10
sampling<-lapply(1:B, function(i) sample(id, replace=T))

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