My task is to determine which ones of these datasets given in the picture are suitable for k-means. My script says that k-means usually performs well on concave structures, however the sizes of the obvious clusters of case 1 differ very strongly, which would indicate a possible bad performance of k-means, right?
So my pick here would be case 2, since the sizes of the 3 clusters are almost identical and the shapes are - however not concave - very dense and case 3 has a lot of noise, which k-means can't handle. Are my thoughts correct?
Note, that i don't actually know any values for the dataset, so it is supposed to be clear by looking at the picture if k-means is suitable