PSYC 202 1st Edition Lecture 7Types of measurements  Observational (previous lecture) Self-Report (previous lecture)- Measurement scales o Nominal Labels or groups Simplest oneo Ordinal Rank or order Educational level, military rank Ex: How often do you drink?- Never, rarely, once in awhile, sometimes, alwayso Interval Magnitude of difference Temperature, sea level, IG, SAT score Uses equal distances between numbers to reflect equal distances in participant responses- Example: IQ of 100 versus 90 is 10 point difference. This is the same as the difference between 70 and 60.o Ratio Absolute Zero Test score, money, weight, distance, age This is THE best scale to use! Has everything! - Numbers can be added, subtracted, divided, etc. has a true zero Ex: Weight: true zero, 100 pounds is more than 50 and 25 pounds, the difference between 100 and 75 is the same as the difference between 150 and 125 pounds. And something can weigh 0 poundso Must ask “does the scale have these four properties?” Magnitude- Less or more than the othero Ex: Height Equal intervals - Weight:o Sally lost 10 lbs (135 to 125 lbs).o Jimmy lost 10 lbs (247 to 237 lbs). Difference means same for Sally &Jimmy (both lost 10 lbs).- Depression level: 0 (none) to 3 (severe) scaleo 0 (none) is less than 1 (mild).o 2 (moderate) is less than 3 (severe). Difference b/w 0 and 1 is not the sameas the difference b/w 2 and 3. Absolute zero- Does the property being measured have a zero quantity?- Speed:o MPH of 0 = not moving.- MPH of 20 is twice as much as MPH of 10o What would not be an absolute zero? Temperature Just because the temperature reads 0 degrees doesn’t mean that there’s no temperature, so this does not have an absolute zero. MPH, however, does have an absolute 0 because 0 MPH means there is no movement  Nominal (labels or categories):- Does not meet any of the 3 properties. Ordinal (ranks or order):- Magnitude only. Interval:- Magnitude and equal intervals only. Ratio:- Meets all 3 properties. (You want to use interval or ratio mostly)o Biases in self-reports Social desirability: research participants are concerned with how they will be perceived and evaluated by researcher and other participants Solutions- Neutral wording- Anonymity- Unobtrusive or Disguised observation Acquiescence (“head nod-ers”!) and Nay-Saying - Solutiono Mix of positively and negatively worded questions A lot of people would rather fill something out on paper if it’s about sensitive topics like sex or abuse, b/c when you ask them directly the answers you may get might not be correct- Or if you ask them about if they have unprotected sex- Archivalo The newest field that psychologists have used to measure something Data collected prior to research question - usually for purposes other than your specific research- e.g., census data, court records, newspaper reports Useful for studying:- Phenomena in the historical past- Changes over time- Rare events (e.g., riots, mass murders, school shootings) Limitations- Concerns about data collection- Insufficient information-