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.
Frequency of cluster occurrence from 2004 to 2011. A: Frequencies of spatial cluster occurrence detected by one of the two methods (Local Moran’s I test or spatial scan statistic). B: Frequencies of spatial cluster occurrence detected by both methods.
