From: Darren Norris <doon75_at_hotmail.com>

Date: Thu, 14 Feb 2008 16:51:51 -0800 (PST)

Date: Thu, 14 Feb 2008 16:51:51 -0800 (PST)

I am modelling (at least trying to) the seasonal component of a variable using lmer. I think I am just about getting the hang of building the models but want to see what the fitted values look like. I need to plot 2 lines on the same graph - the original data ( copy of dataframe below) and the fitted values. I am doing this to a) start to understand how to use R and b) start to understand how to build and compare models.

I have been using books (e.g. The R Book Michael Crawley) and pdf (e.g. time series analysis with R part 1 – Walter Zuccchini and Oleg Nenadic) for reference and if the answer is there (which it probably is) I can’t understand it (I have a very slow dial up connection so even searching nabble frequently crashes)!

An example of the model is:

Scale the annual cycle to be length 1.0:-
with(a_dataframe,length(mean_ind))

[1] 15

index<-1:15

15/4

[1] 3.75

time<-index/3.75

Model (index used as explanatory variable for trend, also allows different intercepts for years as a random effect – I hope):-

mtrend<-lmer(byquarter$mean_ind~index+sin(time*2*pi)+cos(time*2*pi)+(1|factor(byquarter$YEAR)),method="ML")

using “lm” I followed the following process to produce the graph I wanted.

lmodel<-with(a_dataframe,lm(mean_ind~sin(time*2*pi)+cos(time*2*pi)))
plot(time,adataframe$mean_ind,pch=".")

lines(time,predict(lmodel))

How can I do the same with lmer? I have tried a variety of things with “predict”, trying to put the results from lmer as a “groupedData” object etc. But I can’t seem to make it work. Any simple solutions? Many thanks for any help.

Sample data a_dataframe below (I removed NULL rows so row references are not concsequtive):-

YEAR_QUARTER YEAR a_mean

1 2004_2 2004 71.46154 2 2004_3 2004 56.30000 3 2004_4 2004 37.88889 19 2005_1 2005 37.00000 20 2005_2 2005 88.44444 21 2005_3 2005 87.28571 22 2005_4 2005 43.75000 38 2006_1 2006 50.85714 39 2006_2 2006 142.25000 40 2006_3 2006 137.57143 41 2006_4 2006 79.86667 57 2007_1 2007 73.13333 58 2007_2 2007 146.28571 59 2007_3 2007 118.07692 60 2007_4 2007 73.50000

-- View this message in context: http://www.nabble.com/How-to-plot-fitted-values-from-lmer-%28lme4-package%29--tp15492920p15492920.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help_at_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.Received on Fri 15 Feb 2008 - 04:07:30 GMT

Archive maintained by Robert King, hosted by
the discipline of
statistics at the
University of Newcastle,
Australia.

Archive generated by hypermail 2.2.0, at Fri 15 Feb 2008 - 08:30:14 GMT.

*
Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help.
Please read the posting
guide before posting to the list.
*