title: How do I choose k when using k-means clustering with Silhouette function?
body: <p>I've been studying about k-means clustering, and one big thing which is not clear is what Silhouette function really tell to me?</p>
  
  <p>i know it shows that what appropriate k should be detemine but i cant understand what mean of silhouette function really say to me?</p>
  
  <p>i read somewhere, if the mean of silhouette is less than 0.5 your clustering is not valid.</p>
  
  <p>thanks for your answers in advance.</p>