Here's my situation. I need to determine if the incidence of a categorical phenomenon that I have observed in a sample is significantly different from an accepted incidence of the phenomenon published in the literature. I would generally use a Chi square test in this situation but my reference incidence is reported as only a percentage (31.6%) and the incidence in my sample is 35.8% for a sample size less than 50. Basically, I know what I want to do, but don't know what values to enter into the stats software for the reference. Since the reference incidence is reported as a percentage I could use proxy values of 31.6 with a made up N of 100 but I know that the published incidence has been determined from a data set that is in the hundreds of thousands and my fear is that this would alter the calculation....but I can't articulate a specific reason that makes sense why this would happen (the curse of being an amateur).

Any assistance/guidance would be much appreciated. Maybe I am completely off the mark and there is a more appropriate test to apply.

I have access to SPSS, SAS Enterprise Guide, and R, although I am at best minimally proficient at using these but must use the "output" from one of these in my project in order to satisfy the requirements.