Frequencies like Epiinfo
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 at r-project.org
[mailto:r-sig-epi-bounces at r-project.org] On Behalf Of Diego Garcilazo
Sent: 30. november 2010 08:36
To: r-sig-epi at stat.math.ethz.ch; r-sig-epi at 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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