COMM 88 Lecture Notes - Lecture 6: Cortisol, Semantic Differential
4/19/18
●Measurement -- operationalizing variables (both IVs and DVs)
●Types of measures
○Physiological measures
■EX: BP, brain imaging, cortisol (stress hormone)
○Behavioral measures
■EX: nonverbal gestures, time/money spent, actual posts on social media
○Self-report measures
■EX: items on questionnaires
●Levels of measurement
○Nominal (categorical/discrete): Variable is measures merely with different categories
■EX: political party, ethnicity, gender, yes/no Q’s, TV use, persuasive appeal
●Nominal measures are for comparing differences
○between manipulated IV conditions in experiments
○Between existing IV groups in surveys
○Ordinal : variable is measures with rank ordered categories
■EX: rank top 5 favorite TV shows, most to least important political issues
○Interval : variable is measures with successive points on a scale with equal intervals
■EX: measures of attitudes about parenting (strongly agree to strongly disagree
scale)
○Ratio: interval measurement with a true, absolute zero point
■Time in hours, weight in lbs, age in years, test scores, etc.
●This type of measurement allows you to make ratios (interval does not let
you do this)
○Interval & ratio measures are both “continuous” variables
■Allow you to capture more variation
■Can always collapse to categories later, if need be
■Allow you to compare means (avg on DV)
■Allow you to test continuous relationships
●Positive: the more X, the more Y
●Negative: the more X, the less Y
●Using questionnaire items as Measures
Document Summary
Measurement -- operationalizing variables (both ivs and dvs) Ex: bp, brain imaging, cortisol (stress hormone) Ex: nonverbal gestures, time/money spent, actual posts on social media. Nominal (categorical/discrete): variable is measures merely with different categories. Ex: political party, ethnicity, gender, yes/no q"s, tv use, persuasive appeal. Ordinal : variable is measures with rank ordered categories. Ex: rank top 5 favorite tv shows, most to least important political issues. Interval : variable is measures with successive points on a scale with equal intervals. Ex: measures of attitudes about parenting (strongly agree to strongly disagree scale) Ratio : interval measurement with a true, absolute zero point. Time in hours, weight in lbs, age in years, test scores, etc. This type of measurement allows you to make ratios (interval does not let you do this) Interval & ratio measures are both continuous variables. Can always collapse to categories later, if need be. Allow you to compare means (avg on dv)
