Clustering Methods

Abstract

CLUSTERING is a nonparametric method of arranging similar observations together, often in a graphical display used to detect patterns of grouping and outliers. The approach is usually considered nonparametric because there is no specified underlying distribution or model we need to assume. R offers great flexibility in graphical capability making these methods possible. The largest difference between these methods and those considered in the previous chapter is in this chapter we do not know group membership a priori, or whether in fact there are different groups at all. Similarly, part of the methods discussed here includes estimates of the number of dissimilar groups present in the data.