You may find the answer in the website below:

http://www-01.ibm.com/support/docview.wss?uid=swg21480127

Hi Adil

Since the Cochrane-Armitage is a test for trend, 3 or more points are required. So there is little point in doing it on a 2 x 2 table.

About your question, check this out:

http://www-01.ibm.com/support/docview.wss?uid=swg21480127

By the way, you can run the Cochran-Armitage trend test with StatXact.

Those links would be useful if the book cited in their example was available, alswere it is not possible to adapt their example to our context ...

I keep trying to solve this problem, any help is the most welcome.