**Volume Mean, SD, RMS** calculates statistics for the
current set of data
in **Volume Viewer**.

There are several ways to call
**Volume Mean, SD, RMS**, a tool in the **Volume Data** category
(including from the
**Volume Viewer**
**Tools** menu).

Calling the tool calculates the mean, the standard deviation (SD)
from the mean, and the root-mean-square (RMS) deviation from zero for the
current set of data
and reports the results in the
**Reply Log**.
Only data for the current
subregion
and step size are used.
SD and RMS are both root-mean-square deviations,
but the SD is calculated relative to the average value (mean)
whereas the RMS is calculated relative to zero.

UCSF Computer Graphics Laboratory / October 2007