What I meant was: from an unknown number of eggs (maybe 100, maybe 2000) I take 50 eggs and want to see how long before they hatch. when they hatch I know that 50 eggs hatch in 3 days...can I use this number, 3 days, to refer to all the 100 or maybe 2000 eggs from the original group?? I mean, can I say that the eggs of a species hatch in 3 days, even if I just have a subgroup?? If I should use a t-test, for example, I should know the initial population number to know if the 3 days is significant or not, right??