Re: st: Calculating the Medians among group categories

["Austin Nichols" <austinnichols@gmail.com>]

Marcella--
Alan rightly points out that this is a question for an intro stats
book, and easily addressed (insofar as it is possible to address) with
a calculator or paper and pencil.  But I would tackle it in Stata, in
this way:

input str18 v1 v2 v3
"2-bedrooms:    " .    15223372
"with cash rent:" .    14449016
"< $200         " 200  335924
"$200 to $299   " 299  385018
"$300 to $499   " 499  1849604
"$500 to $749   " 749  4898457
"$750 to $999   " 999  3803812
"> $1000        " 1000 3176201
"no cash rent   " 0    774356
end
sort v2
g rs=sum(v3) if v2<.
g fr=v3/rs[7] if v2<.
g cf=rs/rs[7] if v2<.
l v1 v3 fr cf if v2<., noo sep(8)

which tells you (via the cumulative freq var) that 54% have rent below
$750, so the median is close to $750 but somewhat below that value.

On 1/29/07, Alan Neustadtl <alan.neustadtl@gmail.com> wrote:
> You are trying to estimate the 50th percentile from grouped data.
> Many introductory statistics text book cover this kind of problem.  In
> the social sciences you can see "Social Statistics" by Blalock or
> "Statistics for Social Data Analysis" by David Knoke et al. for
> examples.  It is easy to do with a hand calculator.
>
> Best,
> Alan
>
>
> On 1/29/07, Marcella Sapun <msapun@jhu.edu> wrote:
> > Dear Stata Users:
> >
> > I need to get the median rents for a group of renters living in
> > 2-bedroom occupied housing units. I don't have the actual raw data set
> > to derive the medians. But I have a table with the following information
> > on the following Renter-Occupied categories:
> >
> > Categories:                            Estimate total#
> > -------------------------------------------------------------------------
> > 2-bedrooms:                          15,223,372
> > with cash rent:                      14,449,016
> > < $200                                   335,924
> > $200 to $299                         385,018
> > $300 to $499                         1,849,604
> > $500 to $749                         4,898,457
> > $750 to $999                         3,803,812
> > > $1000                                3,176,201
> > no cash rent                          774,356
> > --------------------------------------------------------------------------
> >
> > Does someone have any ideas to compute the median rent (i.e cash rent
> > and no cash rent) among all the groups. Can I do this in STATA?
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