[R] Simulation of data
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 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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and provide commented, minimal, self-contained, reproducible code.
Re: [R] Simulation of data
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
>
> __
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
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