When reading passages like the following:
Based on a representative sample of 88 recent raids, we show that the Turkana sustain costly cooperation in combat at a remarkably large scale, at least in part, through punishment of free-riders.
I wonder what 'representative sample' might refer to.
Is it related to power calculations (for example) in statistical inference or is there some way to assess the number of samples required from the total population for it to be considered representative?