[gmx-users] Difference between Err. Est. And RMSD

[jay patil]

Hi all,
When we get averages from energy file using gmx energy -f *.edr
Output shows Average Err.Est RMSD Tot-Drift.
Which one among Err.Est or RMSD should I use to show error bars in the plot. 
By definition I know RMSD, what is formula for Err.Est. 
Please help.

Thanks

Yogesh