Determining Scale of Measurement 3 steps Examples Try a few

1
Determining Scale of Measurement

• 3 steps
• Examples
• Try a few

2
Scales (levels) of Measurement To determine
level of measurement

• Step 1Identify the Unit of Observation
  (obs unit) (sampling unit)
• (one of something)
• What you are interested on studying?
• Usually the individual (participant) for
  psychologists
• Other possible Observational units
• A rat
• A Group/team
• A Household
• A City
• A Country
• A College student

3
Scales (Levels) of MeasurementTo determine level
of measurement

• Step 2 Ask What am going to do with the Obs
  unit?
• Two options
• Option A Assign the Obs unit to a category
  (quality)
• E.g. gender, race, social security number
  (unique)
• Option B Measure the Obs unit on some attribute
  or behavior
• Intelligence, age, motivational level, number of
  hotdogs eaten
• If Yes to Option A
• Ask are the categories ranked on some quality?
• E.g. job class (clerical I, II, III)
• E.g. class standing (rank in class)
• If NO, not ranked, then level of measurement is
  NOMINAL
• If Yes, categories ranked, level of measure is
  ORDINAL

4
Scales (Levels) of MeasurementTo determine level
of measurement

• If Option B Measure Obs Unit on some attribute
  or behavior
• Step 3 Identify Unit of Measure (Measurement
  Unit)
• One of something (attribute or behavior)
• E.g. item on a test, inventory
• Ask Does the measure have a true zero?
  Usually
• Physical and behavioral ones do
• E.g height, weight, number of cases sold
• Psychological attributes do not
• IQ, need for approval, depression level, attitude
  toward boss

5
Scales (Levels) of MeasurementTo determine level
of measurement

• If answer to Does the measure have a true zero?
• Is YES, level is Ratio
• Is No, level is Interval
• Try out a few

6
What level (scale)? Number of children aboard
each of 15 school buses?

• Observational unit?
• One school bus
• Place bus in category?
• No
• Measurement Unit?
• One student
• Absolute zero?
• Yes, bus could carry no students
• Level of measure?
• Ratio

7
What Level Measurement?Students Fail v. Pass

• Observational unit?
• One student
• Place student in category?
• Yes fail or pass
• Are the categories ranked on some quality?
• Yes (underlying continuous variablesuccess in
  learning)
• Level of measurement?
• Ratio
• Just kidding!
• Ordinal