Principal Component Analysis , Self Organizing Map and Cluster Analysis are used to study the relationship among samples.
These methods are also used to get the summary of the data set.
In the general data type of Multi-Variable Analysis and Data Mining , the data "samples" means the numbers of the data.
For example, when we use Regression Analysis or Pattern Recognition , we do not care about each information of samples. But in the methods in this page, the information is major.
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