From: Frank E Harrell Jr <f.harrell_at_vanderbilt.edu>

Date: Tue 12 Apr 2005 - 03:34:38 EST

Date: Tue 12 Apr 2005 - 03:34:38 EST

Dubas, Joćo Paulo wrote:

> Hello R-listers,

*>
**> I'm working in an experiment that try to determine the degree of
**> infection of different clones of a fungus and, one of the measures we
**> use to determine these degree is the counting of antibodies in the
**> plasma at different dilutions, in this experiment the maximum number of
**> dilutions was eleven. I already checked for differences on the maximum
**> concentration of the antibodies in function of each clone of the fungus.
**> However one measure of interest is the area under the curve (AUC) for
**> the counting of antibodies in function of dilution. Unfortunately I
**> don't know how to calculate the AUC. Someone can point me an example of
**> this procedure or a package that implements this calculation?
**>
**> Thanks for the help,
**> Joćo Paulo Dubas.
**>
*

One of many ways:

trap.rule <- function(x,y) sum(diff(x)*(y[-1]+y[-length(y)]))/2

-- Frank E Harrell Jr Professor and Chair School of Medicine Department of Biostatistics Vanderbilt University ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.htmlReceived on Tue Apr 12 11:07:29 2005

*
This archive was generated by hypermail 2.1.8
: Fri 03 Mar 2006 - 03:31:07 EST
*