Histograms of mean and the coefficient of environmental variation (CVE) for sleep duration. Blue bars denote male line means, pink bars denote female line means, and the difference in line means between males and females (male – female) is shown by purple bars. (a) Night sleep. (b) Male - female night sleep. (c) Day sleep. (d) Male – female day sleep. (e) Night sleep CVE. (f) Male – female night sleep CVE. (g) Day sleep CVE. (h) Male – female day sleep CVE.
Harbison et al. BMC Genomics 2013 14:281 doi:10.1186/1471-2164-14-281