Let's look at each type of scale. These scales assign attributes to different unordered categories. Thus, we measure data by assigning names to them. These are primarily qualitative data that help us to distinguish between or among different class members. Things can be measured nominally in an infinite number of ways because we can assign a name to just about anything.
Nominal data are useful for comparative purposes .
Nominal scales are sometimes referred to as pseudomeasurements because they are qualitative, rather than quantitative data. In ordinal scales we think in terms of greater than or less than . This scale implies that the thing being measured is quantified in terms of being of a higher or lower or a greater or lesser order than the comparable thing. Ordinal scales allow traits, attributes, or characteristics to be ranked without regard to the equality of differences between the ranks. Usually, the mode and the median are reported in regards to ordinal scales.