Hi, Ecologgers I'm struggling in getting the expected means and standard deviation of a ratio between two independent data.
I have data 'A' and 'B' which are population size of two strains of microbe on separate petri dish with a same substrate, the population size of A and B are independent. Now I want to calculate a theoretical ratio of A/B, which may represent the population ratio when A and B are meet at the same petri dish. We want to compare this calculated ratio to the real ratio from experiment. I think the problem is how to calculate the ratio. First what I think is to calculate the ratio of average, which is Average(A) / Average(B), but I fear it should be oversimplifed and also without a standard deviation. Then someone in a statistical forum gave me this: http://en.wikipedia.org/wiki/Taylor_expansions_for_the_moments_of_functions_of_random_variables, which calculate mean and variation by Taylor expansion. But I fell it is way too complex. I wonder if you guys know any similar application in ecology like my situation or any use of the wiki method? Thanks. Zewei
