Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- Home
- /
- Analytics
- /
- Stat Procs
- /
- Re: Exact Binomial CI for Proportion Difference - PROC FREQ

Options

- RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Mute
- Printer Friendly Page

- Mark as New
- Bookmark
- Subscribe
- Mute
- RSS Feed
- Permalink
- Report Inappropriate Content

Posted 10-25-2018 12:21 PM
(2390 views)

What methods are available if there are no responses in a 2x2 table. For example, when analyzing proportion differences between treatments by Gender, neither Male nor Female have any responses (e.g. the counts are zero for both), so FREQ will not estimate the CIs for the difference in proportion. To get around this, I placed a very small non-zero value in the counts table, say 0.000000001 for the zero response counts and then processed it with FREQ using EXACT and RISKDIFF. Should some other method be used, and if so, what is it?

2 REPLIES 2

- Mark as New
- Bookmark
- Subscribe
- Mute
- RSS Feed
- Permalink
- Report Inappropriate Content

- Mark as New
- Bookmark
- Subscribe
- Mute
- RSS Feed
- Permalink
- Report Inappropriate Content

Alright so are the CLs obtained through an ODS table or through an output statement? I tried an output statement but the columns are not easily discerned.

In addition, the small weights do not appear to work as the CI for the risk difference column where the zero weights occur are still showing missing values. Below shows the code I used after applying the small weights.

proc freq data = countsfreq;

by subgroupan subgroupa group ;

table trtp*ev /out = x riskdiff (cl=newcombe) nowarn alpha = 0.1;

weight count/zeros;

/* exact riskdiff;*/

/* ods output riskdiffcol2 = ci1 ;*/

output out = rd2 riskdiff2;

run;

If I use the riskdiff statement my version of SAS only allows (method = score) and with the options above it produces no CI values for the items with zero responses.

Build your skills. Make connections. Enjoy creative freedom. Maybe change the world. **Registration is now open through August 30th**. Visit the SAS Hackathon homepage.

What is ANOVA?

ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.

Find more tutorials on the SAS Users YouTube channel.