On Wed, 18 Aug 2010, chris20 wrote:
Hi,
I am trying to write a function;
I want to subtract the mean of each class in level 2 from the mean of each
class in level 1 and square the answer, eg.....
level.1 level.2 observation
1 1 0.5
1 1 0.2
1 2 0.6
1 2 0.4
2 3 0.8
2 3 0.7
2 4 0.6
2 4 0.4
(mean(1$level.1) - mean(1$level.2))^2
(mean(1$level.1) - mean(2$level.2))^2
etc.....
Chris,
Almost always best to break things into little pieces, like this:
# read data (copy above to clipboard)
dat <- read.table("clipboard",head=T,
+ colClasses=c('factor','factor','numeric'))
# means of level.1
m1 <- coef(lm(observation~0+level.1,dat))
# means of level.2
m2 <- coef(lm(observation~0+level.2,dat))
# all differences
outer( m1, m2, '-')
level.21 level.22 level.23 level.24
level.11 0.075 -0.075 -0.325 -0.075
level.12 0.275 0.125 -0.125 0.125
# all differences squared
outer( m1, m2, '-')^2
level.21 level.22 level.23 level.24
level.11 0.005625 0.005625 0.105625 0.005625
level.12 0.075625 0.015625 0.015625 0.015625
HTH,
Chuck
I want to write a function because I have lots of levels and lots of
different observations.
I thought this should be easy (it's my first attempt at writing a function)
but I just can't work it out!
Thanks
Chris
--
View this message in context:
http://r.789695.n4.nabble.com/functions-and-multiple-levels-tp2329935p2329935.html
Sent from the R help mailing list archive at Nabble.com.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:cbe...@tajo.ucsd.edu UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
