Practical Applications of Data Mining

7.4 Clustering ConCepts 287

7.4.3 Standardization of Variables

In the example of the insured data shown in Table 7.1, we considered two

variables (age and claims). These two variables are measured with different

units. If we examine further, a very important problem arises. The problem

is how to represent variables with different magnitudes in relation to one

another on the same scale. This is a common question because different

variables are often represented in different dimensions (units) as can be seen

from the following examples of representational units:

Counts1. : How many people voted for Ronald Reagan? This unit has no

scale at all.

Ratio2. : The number of moles of an element. This is determined by calcu-

lating a sample’ ...