In my data I have 3 clusters with average silhouette 0.61 and very few negative values. I repeated k-means 10 times with k ranging from 2 to 10. This seemed to work ok, but the problem is that I got those results without scaling from 0 to 1, which I read is a required preprocessing before applying k-means.
Another potential problem is that my correlation matrix is relatively weak compared with iris data set (look at pairs graphics & correlation matrix). Is this a problem for k-means? With all the attributes I tried I got a pretty concentrated pairs graph. Removing outliers and scaling didn't help a lot.
Can I get quality clusters with that kind of data? (first slide1). Do I need to process the data with some other technique first? Or is it that my data are not suitable for applying k-means or other clustering method?