# Re: st: Stata vs SPSS

 From Ronán Conroy To statalist@hsphsun2.harvard.edu Subject Re: st: Stata vs SPSS Date Tue, 17 Oct 2006 10:11:19 +0100

```On 16 DFómh 2006, at 19:17, Richard Williams wrote:

```
```At 11:45 AM 10/16/2006, Georgeta Vidican wrote:
```
```hi there,
try statistics/nonparametric/binomial
i hope it works.
georgeta
```
I don't think that gives you the confidence interval though - at least it didn't as of SPSS 12. My comparisons of how SPSS and Stata handle this sort of problem can be found in
What I meant was a simple descriptive statistic

. ci loneliness, bin wil

------ Wilson ------
Variable | Obs Mean Std. Err. [95% Conf. Interval]
------------- +---------------------------------------------------------------
loneliness | 1337 .3522812 .0130639 . 3271329 .378276

Stata gives the proportion of people who are lonely and the confidence interval. I could not get SPSS to give me the confidence interval and, a couple of years ago, I wrote to tech support to ask how you did it.

They told me that SPSS didn't calculate the confidence interval for a proportion but showed me how it was easy to obtain this, giving me the textbook formula for the standard error of a proportion.

I found this incredible, since any fule kno that using the standard error formula will produce confidence intervals that are too wide and may well exceed the range 0-1.

Stata, on the other hand, embraced Wilson and Jeffreys confidence intervals almost instantly the methods were shown to be the best available - they were slightly beaten to it by Nick Cox. And Stata has had a confidence interval command for a proportion since I started using it (Stata 3).

If it's for social scientists, why does SPSS not have confidence intervals for percentages? These aren't exactly alpha geek stuff...

=========
Ronán Conroy
Royal College of Surgeons in Ireland
rconroy@rcsi.ie
+353 (0) 1 402 2431
+353 (0) 87 799 97 95
www.flickr.com/photos/ronanconroy

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