1. 1 What does a test score of 85 (out of 100) indicate? When you get a test back in class, what is one of the first questions that you ask?

2. 0 10 20 30 40 50 60 70 80 90 100 Test Score Distribution * Low Variability 2

3. 40 45 55 60 70 75 80 90 100 Test Scores 40 45 55 60 70 75 80 90 100 Test Scores Positively Skewed Distribution Negatively Skewed Distribution 3

4. -4  -3  -2  -1  Mean +1  +2  +3  +4  Central Tendency a)Mode (most frequent score) b)Mean (average score; [EX/N]) c) Median (midpoint of scores) Variability (Spread in Scores ) a)Range (lowest to highest score) b)Standard Deviation c) Variance Normal Curve 4

5. X 10 20 30 40 50 -20 -10 0 10 20 Computation of Standard Deviation & Variance x (EX/N) = 30 (Mean) EX = 150 Test Scores Deviation scores (scores minus the mean x2x2 400 100 0 100 400 Squared deviation scores EX 2 = 1000 (Sum of the squared deviation scores) EX 2 /N = 200 (the variance or s 2 ) 200 = 14.14 (standard deviation) s2s2 = standard deviation or s Mean of the sum of the squared deviation scores 5

6. -4  -3  -2  -1  Mean +1  +2  +3  +4  Test Score 13.59% 34.13% 34.13% 13.59% 0.13% 2.14% 2.14% 0.13% Number of Cases Z score T score CEEB score Deviation IQ (SD = 15) Stanine Percentile -4 -3 -2 -1 0 +1 +2 +3 +4 10 20 30 40 50 60 70 80 90 200 300 400 500 600 700 800 55 70 85 100 115 130 145 4% 7% 12% 17% 20% 17% 12% 7% 4% 1 2 3 4 5 6 7 8 9 1 5 10 20 30 40 50 60 70 80 90 95 100 Relationships Among Different Types of Test Scores in a Normal Distribution 6

7. 7 Test Score – Mean Standard Deviation Z SCORE = ~ Standard Score ~

8. Fathers Height (in inches) 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Son’s Height 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 * * * * * * * * * * 8

9. Correlation --- Some Key Concepts a)Consists of a set of ordered pairs b)Indicates both the magnitude and direction of the relationship between variables c)Range is from -1.0 to + 1.0 9

10. Widely Reported Correlations Smoking and lung cancer Media violence and aggression Condom use and sexually transmitted HIV Passive smoking and lung cancer at work Lead exposure and children’s IQ Nicotine patch and smoking cessation Calcium intake and bone mass Homework and academic achievement Asbestos and laryngeal cancer Self-examination and breast cancer -.2 -.1 0.1.2.3.4 From Bushman, B.J., & Anderson, C. A. (2001). Media violence and the American public: Scientific facts versus media misinformation, American Psychologist, June/July, 477-489.

11. Test Scores 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Job Performance 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 * * * * * * * * * * Positive Correlation 11

12. Absenteeism (in hours) 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Job Performance 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 * * * * * * * * * * Negative Correlation 12

13. Test Scores 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Job Performance 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 * * * * * * * * ** ** * * Significant Correlation Poor Good FailPass Correct Acceptances False Rejections Correct Rejections False Acceptances 13

14. Test Scores 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Job Performance 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 * * * * * * * * * * * * * No Correlation Poor Good FailPass Correct Acceptances False Rejections Correct Rejections False Acceptances 14

15. 15 Test Scores Job Performance Scores 100 50 0 100 50 0

16. Test Scores 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Job Performance 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 * * * * * * * * ** ** * * Poor Good FailPass Correct Acceptances Correct Rejections False Acceptances Significant Correlation False Rejections Effect of raising cutoff score?

17. Test Scores 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Job Performance 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 * * * * * * * * ** ** * * Poor Good FailPass Correct Acceptances Correct Rejections False Acceptances Significant Correlation False Rejections Effect of lowering cutoff score?

18. Observation Statement of the Problem (Research Question) Design Study Measurement (Collect Data) Basic Steps in Research Statistical Analysis Interpretation (Conclusion) State Hypotheses Use/Generate a Theory 18

19. ~ Tips for Choosing a Research Topic ~ Read, read, read (e.g., journal articles) to generate research ideas Pick a topic that interests you (it will be more fun to do) Be realistic (pick a topic that can be accomplished in a reasonable time frame) Improve on prior research (e.g., “limitations of present study,” “suggestions for future research”) Minimize problems, time delays in data collection phase of research

20. Basic Scales of Measurement 1)Nominal (Categorization or classification) Yes/No, True/False Male/Female 2)Ordinal (Ranking) 1 st, 2 nd, 3 rd 3)Interval (Equal intervals exist between points on the scale) ___________________________________ 1 2 3 4 5 4)Ratio (an absolute zero point exists) Kelvin scale of temperature Time Height, Weight Measurement : The assignment of numerals to events or objects according to certain rules 20

21. Limit collection of categorical data Age 0 - 18 19 – 25 26 – 35 36 – 45 46 – 55 56 – 65 85 & Above Income 0 ------ 10,000 10,001 – 25,000 25,001 – 35,000 35,001 – 50,000 50,001 – 75,000 75,001 – 100,000 100,000 & Above Age in Years: _______ Income: ____________ ~ I-O Research ~ Measurement

22. ~ I-O Research ~ Measurement (cont.) Yes _____ No _____ _____ _____ _____ _____ _____ 1 2 3 4 5 Highly Disagree Agree Limit collection of dichotomous data

23. ~ I-O Research ~ Measurement (cont.) Restrict possibility of missing data 1. 2. 3. 4. 5. 48 49 50 Scale Questions Missing Computed score for scale or subscales containing questions #5 and #48 will also be missing

24. ~ Key Terms ~ Independent variable (IV) (predictor): One that can be manipulated or used to predict scores on the dependent variable Dependent variable (DV) (criterion): The variable of interest; the one you are attempting to understand or affect SAT, ACT scores used to predict success in college Interview scores used to predict performance in a job IVsDVs 24

25. Design Options ControlRealism Laboratory Experiment Manipulate independent variable Precise measurement of dependent variable Case study Detailed information Low generalizability Naturalistic observation Field study Survey researc h 25

26. ~ I-O Research ~ Interesting fact: Substantial amount of I-O studies are non- experimental (about 50%) Overall Point: Best for research to be driven by theories and problem-solving approaches not by methodology/statistics Much research efforts in I-O focus on rather trivial questions that can be studied with “fancy” techniques Bulk of research has limited applied significance

27. Some Pre-Experimental Designs Static Group Comparison X O O One-Shot Case Study X O X = Treatment or Intervention O = Observation or Collection of Data One-Group Pretest-Posttest Design O X O 27

28. Math Pretest 55 64 44 33 28 63 48 38 46 47 Math Posttest 56 66 46 38 29 63 50 40 48 47 English Pretest 33 35 43 36 20 60 40 31 52 64 English Posttest 35 37 47 36 21 62 40 31 56 66 6-week training program between tests Did the program work to increase scores? 28

29. % increase 100 90 80 70 60 50 40 30 20 10 0 MathEnglish “Lying” with numbers 29

30. An organization reports that accidents have decrease substantially since they began a drug testing program. In 1995, the year before drug testing, the number of accidents was 50. In 1996, the year testing began, the amount dropped to 40. In 1997, the year after drug testing the number of accident dropped to 29. What do you make of this? 1995Drug Testing 55 50 45 40 35 30 25 20 15 10 5 1997 * * * 30

31. 65 60 55 50 45 40 35 30 25 20 15 Given the illustration below, now what do you make of the effectiveness of the drug testing program? 1992 1993 1994 1995 1996 1997 1998 1999 2000 * * * * * * * * * 31

32. Multiple Time-Series Design O 1 O 2 O 3 O 4 O 5 X O 6 O 7 O 8 O 9 O 10 O 1 O 2 O 3 O 4 O 5 O 6 O 7 O 8 O 9 O 10 Some Quasi-Experimental Designs O 1 O 2 O 3 O 4 O 5 X O 6 O 7 O 8 O 9 O 10 Time-Series Design O X O O Non-Equivalent Control-Group Design 32

33. R O X O R O O R indicates randomization Pretest-Posttest Control Group Design R X O R O Posttest-Only Control Group Design Some True Experimental Designs 33

34. 34 ~ Basic Ethics in Research ~  Informed Consent  Right to Privacy  Anonymous, confidential treatment of data  Protection from Deception (cost-benefit assessment)  Debriefing e.g., (explanation of the purpose of the study)

35. 50 45 40 35 30 25 20 15 10 5 0 J F M A M J Jul Aug S O N D At first glance, anything happening here? 35

36. 10 9 8 7 6 5 4 3 2 1 0 J F M A M J Jul Aug S O N D How about now? 36