```Date: Tue, 14 Dec 2004 07:45:38 -0500 Reply-To: Jay Weedon Sender: "SAS(r) Discussion" From: Jay Weedon Organization: http://newsguy.com Subject: Re: How to find center of cluster Content-Type: text/plain; charset=us-ascii On 12 Dec 2004 22:27:50 -0800, brian@homeboys.dk (B Schwartz) wrote: >I have a range of predefined clusters in a 4 dimensional space (one >cluster for each customer type). My problem is I want to calculate the >CENTER OF EACH CLUSTER in order to find the distances between the >clusters. >1) How do I do that - theoretically ? Depends on what you mean by "center". The commonest definition is "centroid", which is simply the vector of means of X,Y,Z,T for cases belonging to the cluster. And on what you mean by "distance". The commonest definition is Euclidean distance, which is the square root of the sum of squared differences, so if your centroids are [X1,Y1,Z1,T1] & [X2,Y2,Z2,T2] then the Euclidean distance between them is Sqrt[ (X1-X2)**2+(Y1-Y2)**2+(Z1-Z2)**2+(T1-T2)**2]. JW ```

Back to: Top of message | Previous page | Main SAS-L page