Levels of Measurement

Question 1

What are Quantifiable variables and how does this relate to levels of measurement?

Answer 1

Variables are measured along some type of underlying dimension or scale. The usefulness of measurement of any variable depends on what the underlying measure or numbers represent. Measurement can be grouped into four levels:
1. Nominal
2. Ordinal
3. Interval
3. Ration
Each level posses the characteristics of the preceding level, plus an additional quality.

Question 2

Nominal

Answer 2

Refers to quality more than quantity. Simply a matter of distinguishing by name e.g. 1 = female, 2 = male. Even though numbers are used, they do not denote quantity, Nominal measurement is like using categorical level of variables.

Question 3

Ordinal

Answer 3

Refers to order measurement. Ordinal scales indicate direction, in addition to providing nominal information. E.g. ranking an experience 9/10 on a ten point scales, tells us it was better than the expected rating of 6/10. Many psych scales/studies use ordinal measurement (low, med, high).

Question 4

Interval

Answer 4

Provides information about order and posses equal intervals. If the distance between 1 and 2 is the same, so is the distance between 7 and 8, on a 10point scale. E.g. Temperature - degrees - represents the same underlying amount of heat, regardless of where it occurs on the scale. Difference between 12 and 26 degrees is the same difference between 28 and 32 degrees.

Question 5

Ratio

Answer 5

In additional to qualities from nominal, ordinal and interval, Ratio has an absolute zero point ( a point where none of the quality being measured exists). Ratio scale permits comparison - being twice as high, or half as much. E.g. reaction times use ration scale.