# Re: st: RE: Cumulative Distribution

 From n j cox To statalist@hsphsun2.harvard.edu Subject Re: st: RE: Cumulative Distribution Date Wed, 28 Sep 2005 12:21:35 +0100

```Modulo a reflection around y = x, this is just
a standard Lorenz curve, as surmised earlier.

A solution from first principles is, as always,
instructive, but canned solutions have long existed
in Stataland. For example,

. search glcurve

Jann Ben

A day ago or two, Ronnie Babigumira wrote:

> I have a data that looks something like this
> par_id	ag_area
> 1	112.2
> 2	91.3
> 3	74.7
> 4	64.3
> 5	57.3
> 6	42.4
> 7	75.4
> 8	77.7
> 9	102.9
> 10	108.0
>
> Where par_id is the parish id (an adminstrative unit), and ag_area, is
> the agricultural area in a given parish
>
> I would like to plot a cumulative distribution of the ag_area. I would
> like a plot that would look something like
>
> ag_area(%)
> 100       * * *
> |      *
> |    *
> |  *
> |*
> |_ _ _ _ _ _ _ __ (number of parishes %)
>                   100

>
>  . cumul par_id [aw=ag_area], generate(c)
>  . scatter c par_id, ylabel(0(.1)1)

But this was not quite it. Meanwhile, Ronnie contacted
me offlist. It turned out that he wanted to plot the
cumulative distribution of ag_area ordered by decreasing
values of ag_area. Thus, the solution is:

. gen df = ag_area
. sum df, meanonly
. local sum = r(sum)
. gsort -df                          // reverse order
. replace df = sum(df) / `sum' * 100 // cumulative area
. gen pc = _n/_N * 100               // proportion of cells
. scatter df pc, ylabel(0(10)100) xlabel(0(10)100)
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```