I've got some data on the time between heart beats of a human. One indication of ectopic (extra) beats is that these intervals are clustered around three values instead of one. How can I obtain a quantitative measure of this?
I'm looking to compare multiple data sets, and these two 100-bin histograms are representative of all of them.
I could compare the variances, but I want my algorithm to be able to detect whether there is one or three clusters in each case without comparing to the other cases.
This is for offline processing, so there's a lot of computation power available, if that's needed.