Nominal Scale
It is the scale where objects are defined based only on differences between them and as having or not having some quality. The example is the scale showing if the man is married or not married.
Ordinal Scale
The ordinal scale is the scale for evaluating the differences between the objects. An example of an ordinal scale is the grading system, such as “very bad, bad, average, good, very good” when it is possible to say that “very good” is better than “good” and thus has a bigger value.
Interval Scale
The scale shows the differences between values by some units and enables to say how some value is bigger or smaller than others. Examples of interval scales are temperature scales, whether Celsius or Fahrenheit, and calendar time measurements.
Ratio Scale
The ratio scale has units connected with each value, similar to the interval scale. However, unlike it, it enables one to divide its values and see how many times one value is larger or smaller than the other, and it has a true zero value, where there is no value at all. The example is a scale of lengths: one can clearly say that a distance of four miles is two times larger than two miles.