A nominal variable is a generalization of the binary variable. Nominal variable has more than two states, For example, a nominal variable, color consists of four states, red, green, yellow, or black.
In Nominal variables the total number of states is N and it is denoted by letters, symbols or integers.
1. An ordinal variable also has more than two states but all these states are ordered in a meaningful sequence.
2. A ratio scaled variable makes positive measurements on a non-linear scale, such as exponential scale, using the formula
AeBt or Ae-Bt
Where A and B are constants.