Robust gene expression index (Q1954505)

Summary: The frequentist gene expression index (FGX) was recently developed to measure expressions of Affymetrix oligonucleotide DNA arrays. We extend FGX to cover non-normal log expressions, specifically long-tailed symmetric densities and call our new index as a robust gene expression index (RGX). In the estimation, we implement the modified maximum likelihood method to unravel the elusive solutions of the likelihood equations and utilize the Fisher information matrix for covariance terms. From the analysis via the bench-mark data sets and simulated data, it is shown that RGX gives promising results and mostly outperforms FGX in terms of relative efficiency of the estimated signals, in particular, when the data are non-normal.