The coefficient of variation (CV), also known as relative standard deviation (RSD), is a standardized measure of dispersion of a probability distribution.
For each group of data (e.g per plate), CVs are calculated for each selected subset (e.g. control wells of a plate).
OriginalCV = sd(x[subset] / mean(x[subset]) * 100RobustCV = mad(x[subset] / median(x[subset]) * 100