PS296 Chapter Notes - Chapter 2: Categorical Variable
Scales of Measurement:
S.S. Stevens defines 4 types of scales:
1) nominal
2) ordinal
3) interval
4) ratio
-scales are distinguished on the basis of the relationships assumed to exist between objects
having different scale values
Nominal scales:
-not really a scale at all
-labels items
-number on the back of a sports jersey
-could just as easily use letters or pictures
-gender is a nominal scale that uses words in place of numbers
-categorical data are often measured on a nominal scale bc we merely assign category
labels whereas quantitative/measurement data are measured on the other 3 types of scales
Ordinal scales:
-orders people, objects, or events along some continuum
-first, second, third place in a competition
Document Summary
S. s. stevens defines 4 types of scales: nominal, ordinal, interval, ratio. Scales are distinguished on the basis of the relationships assumed to exist between objects having different scale values. Number on the back of a sports jersey. Could just as easily use letters or pictures. Gender is a nominal scale that uses words in place of numbers. Categorical data are often measured on a nominal scale bc we merely assign category labels whereas quantitative/measurement data are measured on the other 3 types of scales. Orders people, objects, or events along some continuum. No info given about the differences between points in the scale. Temperature; the difference between 10 degrees and 20 degrees vs 90 degrees and 90 degrees is the same. This scale also satisfies the properties of the two preceding scales. Cannot speak meaningfully about ratios; cannot say 40 degrees fahrenheight is 1/2 as hot as 80 degrees fahrenheit bc the zero point on the scale is arbitruary.
