Thanks again to Kit, a version with the extra -lt- option is now on SSC.
Please install or re-install using -ssc- or -adoupdate- if interested.
The nub of the matter is best shown by an example:
. sysuse auto
. groups rep78, show(F f Rf) lt
+---------------------------+
| rep78 # < Freq. # > |
|---------------------------|
| 1 0 2 67 |
| 2 2 8 59 |
| 3 10 30 29 |
| 4 40 18 11 |
| 5 58 11 0 |
+---------------------------+
. groups rep78, show(F f Rf) ge
+-----------------------------+
| rep78 # <= Freq. # >= |
|-----------------------------|
| 1 2 2 69 |
| 2 10 8 67 |
| 3 40 30 59 |
| 4 58 18 29 |
| 5 69 11 11 |
+-----------------------------+
Nick
[email protected]
Nick Cox
Thanks to Kit Baum, a revised version of -groups- with an extra -ge- option has been placed on SSC. I believe that option suits Stefan's problem.
Stata 8 is required.
For an overview without installation:
. ssc type groups.hlp
For installation or re-installation, use -ssc- or -adoupdate-.
As someone, some day, may want cumulatives to be "less than" rather than "less than or equal to" I will shortly add an -lt- option.
Past Fortran (or FORTRAN) users may enjoy a brief moment of nostalgia.
Nick
[email protected]
Nick Cox
I'll look at -groups- to see if this functionality can be added.
[email protected]
Thanks to Martin, Maarten and Nick for your help!
There are many ways to calculate reverse cumulative distributions in a do file and I already have used that. What I was looking for was a quick and easy solution. I often have people on the phone asking for results and it occurred to me that I couldn't produce this kind of data on the fly (calculation in the head is one option but may be error-prone while talking on the phone).
- "cumul, equal" works, but requires some additional programming.
- "groups, show(rvpercent)" is very flexible but - as far as I see - not exactly what I wanted. Options like RVpercent, rpercent or Rpercent produce reverse cumulative distributions of the type "percentage of cases bigger than x" , not "bigger than or equal to x". It works but for "equal or bigger" one has to pick the result from the previous line.
- reversecum works fine. It's a bit slow (compared to the tabulate-command) with big datasets because of the use of preserve, contract and restore, but produces what I was looking for.
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