| |
Nominal |
Ordinal |
Interval |
Ratio |
|
Examples |
Psychiatric categories, brand names, political or religious
affiliation, gender, left-right handedness, eye-color, etc. |
Rank in your graduating class, rank in a physical or intellectual test
(i.e., 1st, 2nd, 3rd, etc.) |
Test scores, GPA, personality & attitude test scores, etc. |
Weight, length, reaction time, income, etc. |
|
Properties |
Identification: Subjects are identified by a QUALITY they possess NOT a quantity of
something. |
Identification & Magnitude: Subjects are ranked from highest to lowest on some quality. |
Identification, Magnitude, & equal
Intervals. (i.e., the difference between 70 and
80 on a test is the same as between 90 and 100 on the same test.
|
Identification, Magnitude, Equal Intervals, & True Zero Point. |
|
Mathematical Operations |
NONE! You cannot add or subtract
democrats & republicans or blue eyes and brown eyes. |
Rank order only. We know the
person in 2nd place came in behind the person in 1st
place, but not by how much. |
Addition and subtraction ONLY. A
person who scores a 45 on an IQ test scored 45 points less than a person
with a 90. But, you can’t say the person who scored 90 is twice as smart
as the one who scored 45. |
Addition, subtraction, multiplication, and division.
You can say person A is twice as tall as person B or that Person C
makes half as much money as person D |
|
Typical Statistics Used |
Chi-square |
Spearman rank-order correlation |
Pearson product-moment correlation, t-test, ANOVA |
Pearson product-moment correlation, t-test, ANOVA |