Hello!
I want to plot a P-P plot. So I've implemented this function:
ppplot - function(x,dist,...)
{
pdf - get(paste(p,dist,sep=),mode=function);
x - sort(x);
plot( pdf(x,...), ecdf(x)(x));
}
I have two questions:
1. Is it right to draw as reference line the following:
xx -
At 12:57 PM 6/9/2007, Marco wrote:
snip
2.I found various version of P-P plot where instead of using the
ecdf function use ((1:n)-0.5)/n
After investigation I found there're different definition of ECDF
(note i is the rank):
* Kaplan-Meier: i/n
* modified Kaplan-Meier: (i-0.5)/n
*
On 6/9/07, Robert A LaBudde [EMAIL PROTECTED] wrote:
At 12:57 PM 6/9/2007, Marco wrote:
snip
2.I found various version of P-P plot where instead of using the
ecdf function use ((1:n)-0.5)/n
After investigation I found there're different definition of ECDF
(note i is the rank):
*
At 06:36 PM 6/9/2007, Marco wrote:
On 6/9/07, Robert A LaBudde [EMAIL PROTECTED] wrote:
At 12:57 PM 6/9/2007, Marco wrote:
snip
snip
Hmmm I'm a bit confused, but very interested!
So you don't use the R ecdf, do you?
Only when an i/n edf is needed (some tests, such as ks.test() are
based on
