Determine intervals from kernel density estimation
<p>I have a 1-dimensional data which is (t) where users spend time to complete a task. I applied kernel density estimation from <a href="http://www.mathworks.com/matlabcentral/fileexchange/14034-kernel-density-estimator" rel="nofollow">http://www.mathworks.com/matlabcentral/fileexchange/14034-kernel-density-estimator</a> to remove the outliers who spent unreasonable time. I used the following lines:</p>

<pre><code>[bandwidth,density,xmesh]=kde(dur1);
plot(xmesh,density);
</code></pre>

<p>After applying KDE, I have a problem of defining the local minima to split the data. The following link shows how the curve looks like:
<a href="http://s23.postimg.org/6aa1748jf/kde.jpg" rel="nofollow">http://s23.postimg.org/6aa1748jf/kde.jpg</a>
I expect to see three clusters, where the middle one contains the reasonable spent time. However, the curve I have got has only one peak.</p>

<p>I am wondering if the steps I am following are correct?</p>