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/>