I have objects o1, o2,...,on and for each pair I calculate a value that measures the pair's difference. This is a percentage, so for example o1o2 differ by 56%. Now I want to cluster this data. I can see how a hierarchical clustering analysis would fit e.g. o5o6 are the closest pair, now which of the rest are closest to either o5 or o6, and so on.
My question is: can I apply a k-means analysis as well? It seems to me k-means requires (x,y) type data but I may be wrong. Perhaps k-means requires data with levels of measurement: (ratio, ratio) and hierarchical requires (nominal, nominal, ratio)? Or maybe there is a better technique?