Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

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.

View full-text article in PMC

. 2010 Mar 8;118(9):1318–1325. doi: 10.1289/ehp.0901315

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Publication of EHP lies in the public domain and is therefore without copyright. All text from EHP may be reprinted freely. Use of materials published in EHP should be acknowledged (for example, ?Reproduced with permission from Environmental Health Perspectives?); pertinent reference information should be provided for the article from which the material was reproduced. Articles from EHP, especially the News section, may contain photographs or illustrations copyrighted by other commercial organizations or individuals that may not be used without obtaining prior approval from the holder of the copyright.

PMC Copyright notice

(A) Relative homogeneity within towns. Unclassified index values H_s (top) and A_s (bottom) are shown. Each dot is a constituent block-group value; small towns have only one block-group. (Final town values are a population-weighted average of the input block-group variables used to construct the indices.) (B) Relative homogeneity within strata. Each dot is a constituent block-group value of H_s or A_s.