Appropriate statistics to apply- Fishers exact test? - (Jul/29/2012 )

Hi.

I was hoping someone would be able to help me where my supervisors can't!
I'm writing up my M.Sc. dissertation and really stuck on the appropriate statistical analysis to use with my results. My study involved the use of intestinal biopsies from 11 Crohn's disease patients and 4 control patients. I was using PCR to test for the presence of a specific mycobacteria within these biopsies. From my results, I found this mycobacteria in 7 out of 11 of my Crohn's disease biopsies and 0 out of 4 of the control patients. What is the appropriate statistical test to apply to find if this is significant? My research tells me to use the fishers exact test, however, i'm concerned my small sample number just isn't enough to apply this kind of statistical analysis to. I would much appreciate it if someone could advise me!

To me, Fisher's exact test is appropriate because it is good for contingency tables with small numbers.

Hi! Thank you for replying! I'm just concerned that my sample size is so small, that I can't really apply any statistical analysis to the study at all?! Particularly because I have such a small number of controls.