1. Research Methods Psych 402 LECTURE 3 VHS – Teaching Modules Experimental Design (Experimental design, variables)

2. Assignment 1: LIBRARY SEARCH Due Wed 1.Number EEG papers on autism (autism, asperger, autistic) 2.Number of sleep deprivation papers on high school kids 3.Number of subjects in the one study on sleep deprivation, naps, and caffeine in high school kids 4.Number of papers published by Carl Sagan in English 5.Number of sleep papers published since January 1, 1980 6.Number of co-authored papers by DA Kaiser & MB Sterman 7.Maximum score on Autism Spectrum Quotient Test (AQ Test) 8.Maximum female score on the AQ test = CHECK MEDLINE ABSTRACTS 9.Size in grams of Immanuel Kant’s brain 10.Publication year of the one book in Wallace library on a feral/neglected child who was discovered in the 20 th century Use Medline for questions 1-5 PsycInfo for question 6 any source for remainder

3. QUANTIFICATION OF BEHAVIOR Descriptive Statistics Characteristics of your sample –Central tendency –Dispersion Inferential Statistics –How likely your sample reflects the population

4. Mean MEAN is arithmetic average 1 6 5 2 Mean = total divided number of items, 15/5 = 3 PROBLEMS WITH MEANS –EXAMPLE –Kirkwell WA mean per capita income is $1,200K –I survey the gas stations, movie theaters, country clubs, and rarely find anyone at or near this value

5. Means are sensitive to extremes

6. Median is the middle value Arrange in order, middle value is median 1 2  5 6 Median = 2 When even number of items –Arrange in order, average of middle two values 1 2  5  6 7 Median = (2+5)/2 = 3.5

7. Median’s advantage: Not sensitive to extremes 1 2  5 6 Median = 2 1 2  5 6 billion Median = 2 -150 1 2  5 6 Median = 2

8. Example: Kirkwell WA median per capita income is $70K

9. Median disadvantage: it’s nonlinear! (e.g., affected by grouping, other influences) 1 4 Median =1 4 16 Median =4 Median for all numbers = (1+4)/2 = 2.5 1 4 16 Median =4

10. Mode Most frequent value 1  2 5 6 Mode = 1 EXAMPLE Kirkwell WA modal per capita income is $13K –(as it is in all cities)

11. Mode is also nonlinear! 1 4 Mode =1 4 16 Mode =4 Mode for all numbers = (1+4)/2 = 2.5 1 4 16 Mode =4

12. How well central tendency describes data? - Needs index of dispersion 1 2 3 4 5 6 7 8 9 Mean = 5 4 5 6 Mean = 5

13. Dispersion: Range 1 2 3 4 5 6 7 8 9 Mean = 5, Range = 8 4 5 6 Mean = 5, Range = 2

14. Dispersion: Standard Deviation (Std Dev takes into account each sample’s distance from mean) 4 5 6 Mean = 5, Range = 2 St Dev = 0.88 4 5 6 Mean = 5, Range = 2 Std Dev = 0.44

15. Measurement Scales 2. The Measurement Principles Nominal or categorical OrdinalIntervalRatio Same scale value are the same on some attribute. No 'numeric' meaning in the way that you usually think about numbers. Higher scale value indicates more of some attribute. Intervals between adjacent values vary Intervals between adjacent values are equal on attribute E.g., difference between 8 and 9 is same as difference between 76 and 77. Meaningful zero point Ratios are equivalent, e.g., ratio of 2 to 1 is the same as the ratio of 8 to 4. Each "higher" level of measurement includes the measurement principle of the "lower" level of measurement. For example, the numbers 8 and 9 in an interval NominalOrdinalIntervalRatio Gender. Ethnicity. Marital Status. SES USDA beef ratings (good, choice, prime) Hospitalization Rank order of anything. Degrees F. Letter Grades IQ, SAT Degrees K. Annual income in dollars. Time or distance

16. Role of Figures in Scientific Papers Argument made in pictures, not words!

20. Figures used for: DATA METHOD THEORY Compress information

21. Three mountain test for egocentrism

24. Hierarchical memory storage

25. Lying with statistics

27. Assumed linearity

28. Lie Factor = Size of effect shown in graphic/size of effect in data

29. Quantify Brain Behavior (EEG)

30. Quantify Eyetracking

34. Ages, wealth, length of absence

38. RESEARCH VARIABLES Independent variable (IV): Variable manipulated by researcher Dependent variable (DV): Variable measured by researcher, expected to change as a result of researcher’s manipulation (“depends on IV”) Control variables (CV): Factors kept constant (e.g., confederate, room). Random variables (RV): Factors allowed to vary randomly. (e.g. time of day effects, fatigue, motivation) Confounding variable: Variable’s levels covary with IV’s and may be responsible for changes

39. My hypothesis: –When people are angry, they drive more aggressively IV: Anger –Level 1. Drop 5 lb weight on subject’s foot 3 or 4 times –Level 2. Drop feather on subject’s foot 3 or 4 times DV: Aggressive driving –How can I quantify aggressive driving?

40. Are aggressive people aggressive drivers?

41. OPERATIONAL DEFINITION Specify operations required to manipulate or measure concept. e.g. Anxiety is not vaguely described but explicitly measured by objectively through subjective report scales, behavior checkboxes, etc