I have a large set of items and, two-by-two, there exists some kind of attraction/repulsion that I have measured.

Under different circumstances this attraction/repulsion changes.

So, what kind of statistical/mathematical procedure can I use to measure whether the changes (for the whole set) are “large/small”, as well as if a subset of them (lets say the first ten items) the attraction is larger than in another subset (lets say the last ten items)?.

Thanks in advance