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List:       r-sig-epi
Subject:    Re: [R-sig-Epi] Frequencies like Epiinfo
From:       "BXC (Bendix Carstensen)" <bxc () steno ! dk>
Date:       2010-11-29 22:55:04
Message-ID: 2F73FA3AF524144C863B7C2C903DBC3302B665D265 () exdkmbx002 ! corp ! novocorp ! net
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Inside the function twoby2 from the Epi-package you will find a small locally defined \
function that gives you confidence intervals for proportions that are better than \
those you compute, which occasionally will give limits outside (0,1).  This one is \
based on the logit approximation, and is what you get if you used a logistic \
regression to estimate the proportions:

bin.ci <- 
function(x, n) 
{
  ef <- exp(qnorm(1 - alpha/2)/sqrt(x * (n - x)/n))
  p <- x/n
  c( p, p/(p + (1 - p) * ef), p/(p + (1 - p)/ef))
}

Best regards,
Bendix Carstensen

> -----Original Message-----
> From: r-sig-epi-bounces@r-project.org 
> [mailto:r-sig-epi-bounces@r-project.org] On Behalf Of Diego Garcilazo
> Sent: 30. november 2010 08:36
> To: r-sig-epi@stat.math.ethz.ch; r-sig-epi@r-project.org
> Subject: [R-sig-Epi] Frequencies like Epiinfo
> 
> 
> 
> 
> I am trying to make a function that works like the command 
> Frequencies of Epiinfo. I am a beginner user and I make 
> something like this:
> 
> 
> 
> freq<-function(x){
> 
> Frecuencia<-table(x,exclude=NULL);
> 
> Porcentaje<-as.vector(round(prop.table(table(x,exclude=NULL)),2));
> 
> Porc<-as.vector(round(prop.table(table(x,exclude=NULL))*100,1));
> 
> Acumulado<-cumsum(Porc);
> 
> IC95.Sup<-round(as.vector(Porc+196*sqrt(Porcentaje*(1-Porcenta
je)/sum(Frecue
> ncia))),1);
> 
> IC95.Inf<-round(as.vector(Porc-196*sqrt(Porcentaje*(1-Porcenta
je)/sum(Frecue
> ncia))),1);
> 
> matrix(
> 
> c(Frecuencia,sum(Frecuencia),Porc,round(sum(Porc),1),
> 
> Acumulado,NA,IC95.Inf,NA,IC95.Sup,NA),length(Frecuencia)+1,5,
> 
> dimnames=list(c(labels(Frecuencia)[[1]],"Total"),c("Frecuencia
> ","Porcentaje"
> ,"Acumulado","[IC--","--95%]"))
> 
> );
> 
> }
> 
> 
> 
> There is a way more efficient to create a function like this?
> 
> there is a way to make it more visually - friendly adding 
> something like
> -------------- that stat.table does?
> 
> How can I add an argument like missing=T that show NA's and 
> missing=F that exclude Na's??
> 
> 
> 
> Thanks in advance. 
> 
> 
> 
> Diego. 
> 
> 
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> 
> 	[[alternative HTML version deleted]]
> 
> _______________________________________________
> R-sig-Epi@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-sig-epi
> 
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