Ordinal scales of measurement
Arithmetic operations that can be performed on values assigned
scales are also limited. As well as counting the numbers in
each category on the scale it is possible to indicate relative
size using equals (=), greater than (>) or less than (<)
Any operation involving addition and subtraction is not allowed
- for example calculating the mean.
Calculating the median
as measures of central tendency is OK as these only involve
counting the numbers in each category on the scale.