The values given are black and white without a paicular structure. Which is the scale used in classification?

A nominal scale, as the name implies, is simply some placing of data into categories, without any order or structure. The lowest impoant measurement level, from a statistical point of view, is a nominal scale. An ordinal scale is next up the list in terms of power of measurement. The simplest ordinal scale is a ranking. The standard survey rating scale is an interval scale. It is an interval scale because it is assumed to have equidistant points between each of the scale elements. A ratio scale is the top level of measurement and is not often available in social research. The factor which clearly defines a ratio scale is that it has a true zero point. The simplest example of a ratio scale is the measurement of length.