topic Re: Exact confidence interval for the difference of 2 binomial proportions. in SAS Health and Life Sciences

Exact confidence interval for the difference of 2 binomial proportions.

deleted_user — Tue, 09 Oct 2007 08:42:14 GMT

Hi all,

SAS does not compute an exact confidence interval for the difference of 2 binomial proportions. Does anybody know how to do this?

Many thanks for your help,

Violaine

Re: Exact confidence interval for the difference of 2 binomial proportions.

Cynthia_sas — Tue, 09 Oct 2007 14:33:21 GMT

Hi:
Perhaps these will be useful:
Statistics FAQ: http://support.sas.com/techsup/faq/stat_key/a_j.html (look under binomial)
http://support.sas.com/techsup/faq/stat_key/k_z.html
http://support.sas.com/faq/009/FAQ00922.html
http://support.sas.com/faq/009/FAQ00925.html
http://support.sas.com/faq/042/FAQ04291.html
http://support.sas.com/faq/041/FAQ04144.html

cynthia

Re: Exact confidence interval for the difference of 2 binomial proportions.

deleted_user — Tue, 09 Oct 2007 15:29:13 GMT

Many thanks for your help,

Violaine

Re: Exact confidence interval for the difference of 2 binomial proportions.

deleted_user — Wed, 31 Oct 2007 12:42:42 GMT

Dear all,

I get back to you regarding the calculation of the 95% exact CI for the difference between 2 binomial proportions. For this matter, I would like to use the CT (Coe & Tamhane) method. Coe wrote a SAS macro for this matter (“A SAS® Macro to Calculate Exact Confidence Intervals for the Difference of Two Proportions”, which is a free article), and he explained in another article (“Small sample confidence intervals for the difference, ratio and odds ratio of two success probabilities”, which I will not be able to forward you) the steps of the algorithm for performing the 95% exact CI for the difference between 2 binomial proportions.

Does anybody have read this article? If yes, maybe you can help me… I am stuck at the Step 2.1.
I don’t understand how a min function can be used since to my mind, there is always once delta per acceptance region.

I am really embarassed because I can’t progress! I would be glad if someone could help me!!!

Many thanks in advance,

Kind regards,

Violaine