What you describe is called stratified sampling. It was discusssed last
month (and other times) on this list:
http://finzi.psych.upenn.edu/R/Rhelp02a/archive/90220.html
Using
RSiteSearch(stratified sampling)
will produce many hits to relevant articles and packages.
On Mon,
I have a full data set like this:
aa basaas bms ams bcuacu omega y
1 ALA 0 127.71 0 69.99 0 -0.2498560 79.91470 outward
2 PRO 0 68.55 0 55.44 0 -0.0949008 76.60380 outward
3 ALA 0 52.72 0 47.82 0 -0.0396550 52.19970 outward
4 PHE 0 22.62 0
Aimin Yan wrote:
I have a full data set like this:
aa basaas bms ams bcuacu omega y
1 ALA 0 127.71 0 69.99 0 -0.2498560 79.91470 outward
2 PRO 0 68.55 0 55.44 0 -0.0949008 76.60380 outward
3 ALA 0 52.72 0 47.82 0 -0.0396550 52.19970 outward
