My logic:
Measurement from single entities (one county with it sample) has its
own error. Combining multiple single measurements will create sum or
error from each measurements.
IF
On Tue, Mar 12, 2013 at 12:18 PM, <liang.long(a)dot.gov> wrote:
I can see why Census doesn't recommend do more
than three variables at a time. When you add 17 counties together, you get a much bigger
area with more households sampled. In theory, you should get a smaller MOEs compared each
individual county. But if you derive MOEs from those 17 counties, you will get a much
bigger MOEs, which is contradictory to the theory.
________________________________________
From: ctpp-news-bounces(a)chrispy.net [ctpp-news-bounces(a)chrispy.net] on behalf of Ed
Christopher [edc(a)berwyned.com]
Sent: Tuesday, March 12, 2013 11:15 AM
To: ctpp-news(a)chrispy.net
Subject: Re: [CTPP] Working with County flow data
Thanks--I know the spread sheet allows you to recalculate MOEs for more than three
variables but I remember doing more than 3 a while back and I was getting some wild MOEs.
When I dug into it I found something in the Census compass reports that said not to do
more than three variables at a time. I was hoping that someone figured out a way around
this.
Ed C
On Mar 12, 2013, at 9:59 AM, "Hoctor Mulmat, Darlanne"
<Darlanne.Mulmat@sandag.org<mailto:Darlanne.Mulmat@sandag.org>> wrote:
The New York State Data Center developed a Statistical Calculations Menu that includes an
option for computing the margin of error for the sum of three or more estimates. See
attached.
Darlanne Hoctor Mulmat
Applied Research Division – Criminal Justice/Public Policy
San Diego Association of Governments
619-699-7326
From: ctpp-news-bounces@chrispy.net<mailto:ctpp-news-bounces@chrispy.net>
[mailto:ctpp-news-bounces@chrispy.net] On Behalf Of
Ed.Christopher@dot.gov<mailto:Ed.Christopher@dot.gov>
Sent: Tuesday, March 12, 2013 6:57 AM
To: ctpp-news@chrispy.net<mailto:ctpp-news@chrispy.net>
Subject: [CTPP] Working with County flow data
Has anyone come up with some easy ways for collapsing and grouping counties together
using last week’s county flow data and recalculating new MOEs. I have so many counties
that I want to group together that I am looking for a quick way that can handle “lots” of
counties. Another issue I am struggling with is that we are always told not to group more
than three variables at a time or the formulas for calculating the new MOE do not really
work. This is particularly troublesome especially if I am trying to group 17 counties
together. What it comes down to is 9 different calculations given that I can only group 3
counties at a time together. Anyone figure out any short cuts or ways around this short
of disregarding the MOEs altogether? Given all the clustering that I am looking at using
the “cheat” sheets I am used to, I will be recalculating MOEs for weeks.
Ed Christopher
<StatisticalCalculationsMenu.xls>
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