Ordinal scale is the lowest level of scale. It places events in order but there is no attempt to make the intervals of the scale in regard to any rule. Order scales are represented by rank orders basically used in research relating to qualitative phenomenon. An example of student’s rank in his graduation class involves the use of an ordinal scale.
The usage of ordinal scale means a statement of ‘greater than’ or ‘less than’ without being able to tell how much greater or lesser. There could be real difference between ranks 1 and 2 maybe less or more than the actual difference between ranks 5 and 6.
The right measure of central tendency is the median since the number of this scale has only a rank meaning. In order to measure dispersion, a percentile or quartile measure is used. Correlations are restricted to different rank order methods whereas measures of statistical importance are constrained to the non-parametric methods.