PS276 Lecture Notes - Physical Attractiveness
Scales of Measurement
-4 main scales of measurement
-the way variables are defined and categorize
-how variables are qualified and quantified
-which scale you use determines how you can run statistics
-only with interval and ratio scales can you run sophisticated statistics
1) Nominal (most basic)
-numbers assigned to items represent categories
-numbers assigned to categories are arbitrary/one is not better than another
-ex 1 = male rat, 2 = female rat
-numbers are just labels
2) Ordinal
-numbers assigned to items represent categories that are rank ordered
-there is a hierarchy or ranking to the categories
-ex in a marathon 1, 2 and 3 represent first, second, and third place finishers
-first may have finished in 1 minute, but second in 3 and third in 10
-top 3 highest marks on midterm
3) Interval
-numbers still represent categories and rank but there is now equal distance between these numbers
-numbers have equal units of measurement with no true zero
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Document Summary
Which scale you use determines how you can run statistics. Only with interval and ratio scales can you run sophisticated statistics: nominal (most basic) Numbers assigned to categories are arbitrary/one is not better than another. Ex 1 = male rat, 2 = female rat. Numbers assigned to items represent categories that are rank ordered. There is a hierarchy or ranking to the categories. Ex in a marathon 1, 2 and 3 represent first, second, and third place finishers. First may have finished in 1 minute, but second in 3 and third in 10. Top 3 highest marks on midterm: interval. Numbers still represent categories and rank but there is now equal distance between these numbers. Numbers have equal units of measurement with no true zero. Zero does not represent the absence of the variable. Ex 0 degree celcius does not mean there is no temperature, zero still exists and is a temperature.
