[R] Xyplot - adding model lines to plotted points

[Sandeman, L. R.]

Hello,

I have written code to plot an xyplot as follows:

library(lattice)
xyplot(len~ageJan1|as.factor(cohort),groups=sex,as.table=T,strip=strip.c
ustom(bg='white',fg='white'),data=dat,
xlab="Age (January 1st)",ylab="Length (cm)",main="Linear models for male
and female cod, by cohort",type='p',
lwd=1.5,auto.key=list(text=c("Male","Female"),points=F,rectangles=F,line
s=T))

I have fitted a linear model to the same data (for each sex in each
cohort(year)).  I would like to add the fitted models to the existing
plot (one line for male and one for female, where each panel is a
separate cohort - as in the above code....).  I also want to do this
with non-linear models if possible.

I have trawled R help, and it seems that panel.superpose may be one
method of attempting this, however, I am unable to produce any working
code.

My dataset is too large to put in as an example, but it is in the basic
form as below (where sex is 1 for male and 5 for female).

   len age fitted_model cohort sex
1   24   2 30.05771   1977   1
2   31   3 36.64122   1977   1
3   22   2 27.73938   1978   1
4   34   3 36.64122   1977   1
5   22   2 27.73938   1978   1
6   31   3 36.64122   1977   1
7   34   3 36.64122   1977   1
8   28   2 27.73938   1978   1
9   23   2 27.73938   1978   1
10  24   2 27.73938   1978   1
11  25   2 27.73938   1978   1
Etc...

Any suggestions would be greatly appreciated,

Thankyou,

Lillian.

----------------------

Lillian Sandeman
PhD Student
Zoology Building
University of Aberdeen
Tillydrone Avenue
Aberdeen
Scotland
AB24 2TZ
Tel.: +44 (0)1224 272395
E-mail: l.sandeman at abdn.ac.uk