Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Histogram of z-values for N = 7128 genes in a microarray study comparing two types of leukemia. The N(0, 1) theoretical null is much narrower than the histogram center; a normal fit to the central histogram height gives empirical null N(.09, 1.682). Both curves have been scaled by their respective estimates of p0 in (7).
