building mean/median over subgroups
On Wed, 14 May 2003 15:25:57 +0100
Frank Mattes <f.mattes at rfc.ucl.ac.uk> wrote:
Dear all, I'm trying to solve the following problem, and hoping to get some advise here from the group I have a dataframe in which the same sample was measured more than once on the same day. I would reorganize the dataframe to get a single value (mean /median) for one day Patient Day Sample Test A 1 A 23 A 1 A 36 A 5 B 44 A 5 B 23 B 2 C 10 B 2 C 5 mean Patient Day Sample Test.mean A 1 A 29.5 A 5 A 33.5 B 2 C 7.5 it would be great to get some help form the list. Yours Frank -- Frank Mattes, MD e-mail: f.mattes at ucl.ac.uk
There are examples like this in Section 4.2 of http://hesweb1.med.virginia.edu/biostat/s/doc/splus.pdf --- Frank E Harrell Jr Prof. of Biostatistics & Statistics Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences U. Virginia School of Medicine http://hesweb1.med.virginia.edu/biostat