[R] trajectory plot (growth curve)

[Lei Liu]

Hi there,

I want to make trajectory plots for data as follows:

ID      time    y
1       1       1.4
1       2       2.0
1       3       2.5
2       1.5     2.3
2       4       4.5
2       5.5     1.6
2       6       2.0

...

That is, I will plot a growth curve for each subject ID, with y in 
the y axis, and time in the x axis. I would like to have all growth 
curves in the same plot. Is there a simple way in R to do it? Thanks a lot!

Lei Liu
Associate Professor
Division of Biostatistics and Epidemiology
Department of Public Health Sciences
University of Virginia School of Medicine

http://people.virginia.edu/~ll9f/