Unigene microarray log plots. Five human Unigene microarrays from the panel of thirty-one microarrays used in the sigmoidal colon experiments. Upper left to lower right: a. Loge median gene intensity vs. loge rank – conformity to Zipf's law is demonstrated by the linear regression line (in red) b. Five microarrays chosen to maximize pre-normalization variability, each plotted according to the gene ranks determined by their median gene intensity levels. c. The same five microarrays, normalized to a global mean, with regression lines. d. The same five microarrays, normalized with the quantile method, with regression lines. e. The same five microarrays, normalized taking Zipf's law into account, with regression lines. For plots b-d, a sub-sample of 10% of the data points are plotted for readability.