where kj is the number of gene expression values in sample j, p is the number of samples, and Y¯Q,j is the median gene cluster expression value in sample j. Note that the original implementation of Gene Recommender used the mean gene cluster expression value in the numerator of ZE(j) [26]; later versions of the algorithm used the median [28]. Here we used the latest version. V^Q,j is the sample variance, given by
