[R] tapply
crmontes at ncsu.edu
crmontes at ncsu.edu
Tue Apr 10 00:14:15 CEST 2007
Hi,
I have a summary table for an experiment that looks like this
STUDY BLOCK TREATMENT MEASURMENT RESPONSE
A 1 T-0 1 12
A 1 T-1 1 52
A 1 T-0 2 12
A 1 T-1 2 65
and so on...
there are 10 studies, 4 blocks, 10 treatemnts, 5 measurments for
the response value.
I want to produce a table that looks like this:
STUDY BLOCK TREATMENT MEAS.1 MEAS.2 MEAS.3
A 1 T-1 15 54 65
A 1 T-2 54 65 45
A 2 T-1 12 12 23
A 2 T-2 65 54 65
and so on...
with tapply(RESPONSE, list(TREATMENT, MEASUREMENT, BLOCK, STUDY), mean)
I get very close, however, I get the results as a list!
if instead I use
ftable(tapply(RESPONSE, list(TREATMENT, MEASUREMENT, BLOCK, STUDY), mean))
I get REALLY close, but the I get only one value for each class, however I
need to whole table, because at the end, what I really need is the
increment between MEASUREMENT (n) - Measurement (n-1) for each TREATMENT,
BLOCK, STUDY, to perform a ANOVA analysis over increment data.
Esentialy, I want to move away from running a pivot-table in ACCESS
Any thoughts?
Cristian Montes
North Carolina State University
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