Well,
Yes, that works just fine! Thank you!
--
Michal J. Figurski
HUP, Pathology & Laboratory Medicine
Xenobiotics Toxicokinetics Research Laboratory
3400 Spruce St. 7 Maloney
Philadelphia, PA 19104
Henrique Dallazuanna wrote:
Try using aggregate:
aggregate(tb[-1], list(tb$Subject), FUN=median, na.rm = T)
On Tue, Jun 10, 2008 at 10:18 AM, Michal Figurski
<[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:
Hello everyone,
I am new to R, I have been using SAS for a while. Not surprisingly,
I find R much better in graphics, which is publication ready right away.
Recently, I have been trying to calculate some basic statistics
using R. I have a dataset of multiple rows per subject. For example:
Subject Date Factor1 Factor2 Factor3
P1 0.5 1 1 3
P1 1 3 2 5
P1 2 3 5 NA
...
P2 0.5 1 6 4
P2 1 2 NA 7
P2 2 3 1 2
...
I wanted to get the 'by subject' statistics of the factors. I used
the following code: a=by(dat1, dat1$Subject, mean, na.rm=TRUE) -
this is for a mean.
However, when I try that with a 'median', I get an error message. It
is strange to me, because with the 'summary' option, I get the
median values for all factors separately, among other information.
What I need is just a median, because I later need it for plotting.
I have read old posts on the archive, and I agree that the action of
'median' is according to the documentation. However, I think this is
a serious inconvenience, and it should be changed to work in the
same way as mean, summary or sd options.
Nevertheless, accepting the reality, I have a question to all: how
to obtain the by-subject medians of factors in such dataset?
Thanks in advance,
--
Michal J. Figurski
HUP, Pathology & Laboratory Medicine
Xenobiotics Toxicokinetics Research Laboratory
3400 Spruce St. 7 Maloney
Philadelphia, PA 19104
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--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
______________________________________________
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and provide commented, minimal, self-contained, reproducible code.
