I am interested in the size of an animal in two populations, and found reliable estimates of the population provided by NOAA. The data was in the form of estimated total population within discrete size intervals, presented like so:
Size Pop1 Pop1_Norm Pop1_Cumul Pop2 Pop2_Norm Pop2_Cumul 21 584.14 1.15E-06 1.15E-06 5092.75 9.28E-05 9.28E-05 22 98365.15 0.000194238 0.000195391 503.38 9.18E-06 0.000102018 23 41899.32 8.27E-05 0.000278128 5723.3 0.000104337 0.000206355 ...
Pop1 and 2 represent the number of individuals at a given size, the Norm columns represent the fraction of the total population, and the Cumul columns the cumulative proportion of individuals at or below the given size class. Unfortunately, I don't have access to the raw sample data, and so understand I can't do any inference myself.
However I'd still like to quantify the difference in the population distributions. What are the best methods for describing differences between two populations? Should I just take the difference of the means? What methodological problems do I face working with an estimate of the true population distribution?
I have graphed the cumulative size distributions of these populations, now how can I describe the difference?