I suggest you take a look at appendix 3 in the handbook below
http://www.census.gov/acs/www/Downloads/handbooks/ACSResearch.pdf
____________________________
Eric W. Kramer, Ph.D.
Senior Research/Statistical Analyst
177 N. Church Ave, Suite 405
Tucson, AZ 85701
(520) 792-1093 x506 (tel)
(520) 620-6981 (fax)
ekramer@pagnet.org
From: ctpp-news-bounces@chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Cook, Cliff
Sent: Monday, January 03, 2011 11:24 AM
To: ctpp-news@chrispy.net
Subject: [CTPP] How to Combine Median Values for Mutliple Areas
I am looking for guidance on how to combine median income values for several census tracts into a single value and associated margin of error. I recall seeing something about this topic in an ACS document but cannot locate the information at this time. Any help would be appreciated.
Cliff Cook
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Clifford Cook
Planning Information Manager
Cambridge Community Development Dept.
344 Broadway
Cambridge, MA. 02139
617/349-4656 FAX 617/349-4669 TTY 617/349-4621
email => ccook@cambridgema.gov
web site => <http://www.cambridgema.gov/~CDD/>