Hi
I want to sample several (thousands) of animals and analyse whether they have a certain biomarker or not (YES/NO). The animals will be of differnet age groups, from several counties and of different sex. The distribution of categories will differ i.e. the percentage of females sampeled will differ between counties/age groups etc. How do I go about determining the effect of age, sex and origin on the prevalence of the biomarker?

Im using Excel and R.

Thank you for your reply!