However, posting student grades with a private coding system is legal, and private. Your code identifies you and your grade, and if you do not tell others, is known only to you. Obviously, you cannot perform any statistics on nominal data. Ordinal Another Latin verb ordinare means to put items in order. That describes the ordinal data type well.
Ordinal data have the mathematical property of indicating order or place.
For instance, knowing that a horse finished second is an ordinal datum. Notice that just knowing that second place finish does not tell you anything about how close or how distant that place was. Interval Interval data do provide information about the distance between data points. A scale is a very common way that social scientists provide interval data. Good physical examples are the common temperature scales, centigrade and fahrenheit.