[R-sig-ME] repeated measures on split plot design

Lea mwiederm at mtu.edu
Fri Mar 13 16:47:16 CET 2015


I am hoping for help with formulating the random structure for a data set
that fits a log normal distribution. The data was collected from a split
plot designed experiment (block: 4 replicates; v treatment: 3 levels; d
treatment: 2 levels). d is nested within v which is nested within block; 
total n = 4x3x2 = 24; my random effects are all categorical
hence using lme: random= ~1|block/veg, or lmer: (1|block/veg)

I think I am OK with that but I can not figure out how to include the
temporal repeated measure. This split plot setup was samples 5 times
(monthly during the summer) for 3 years-> 15 times and I am too interested
in the month and year effect. Ergo I do not want to average it out. Also
from plotting the data there is an increase of the response throughout the year.

Most everybody seems to be using the lme4 and not the nlme package these
days. Is there still someone who could help me to write the temporal
structure of the random term using the nlme package?

my fixed factors are: v*d*year*month (I am not interested in the block
effect) my fixed effects are all categorical

m1<-lme(response~v*d*year*month, random= ~1|block/veg  and what do I do with
the 15month in 3 years????


m2<-lmer(response~v*d*year*month+(1|block/veg  and what do I do with the
15month in 3 years????

Thank you so much! 

p.s.: I hope I don't offend anybody by writing things out for both packages.

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