This is a bit of a long-shot, but I'm in need of some statistics help.
Does anyone out there know how to calculate the Standard Error of the Mean (SEM) for a set of data given the SEM from two subsets of the data?
I'm looking at a paper here that divides the results up into two mutually exclusive and exhaustive subsets. Let's call them Red and Blue. I don't have the original data, but I have the mean and SEM of the Red and Blue samples, and I know the size of each. It's trivial to calculate the mean for the overall set, but can I recover the overall SEM?
Wikipedia tells me that "If the standard error of several individual quantities is known then the standard error of some function of the quantities can be easily calculated in many cases;" Is this as trivial as doing a weighted average of the two samples' SEMs the same way I would to calculate the overall mean?
Update: Solution can be found here.