This function calculates the skewness across data for each sample run.
run_skewness(data_only)a \(p \times n\) data.frame, where \(p\) is the number of peptides and \(n\) is the number of samples.
data.frame with two elements: Sample, a character vector giving the sample names; and Skewness, a numeric vector giving the skewness values
Skewness is calculated as a bias-corrected calculation given by
method 2 in the e1071 package. Within a sample NA values are
ignorned in the skewness calculation. If all peptide abundance values are
missing within a sample, the skewness is replaced by the overall mean of
nonmissing skewness values for the data.