varianceBasedfilter: To filter genes according to expression variability
Description
Those genes not significantly more variable than the median gene are filtered out.
Usage
varianceBasedfilter(exprs,p)
Arguments
exprs
a data frame or matrix with rows for variables (genes) and columns for samples.
p
the probability cut-off of the chi-squared model of the gene-specific variance-like statistics.
Value
A data frame or matrix with a reduced number of rows.
Details
This is an approximate test of the hypothesis that gene has the same variance as the median variance. A statistical significance criterion
based on the variance can be used. If the significance criterion is chosen, then the variance of the log-values for each gene is compared to
the median of all the variances. The quantity for each gene compared to a percentile of the chi-square distribution with n-1 degrees of freedom.
Those genes not significantly more variable than the median gene are filtered out [BRB-ArrayTools Version 3.7].
References
Dr. Richard Simon & Amy Peng Lam, BRB-ArrayTools (v3.7) User's Manual: 'Log expression variation filter'.