1. Consists of a set of ordered pairs Indicates both the magnitude and direction of the relationship between variables Range is from -1.0 to +1.0 Correlation --- Basic Concepts

2. 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 * * * * * * * * * *

3. Consider these --- A correlation exists between: The total amount of losses in a fire and the number of firemen that were putting out the fire Cigarette smokers and lower GPAs The number of churches in a city and amount of alcohol consumed The amount of fat in diets and cancer rates

5. Good Poor False Rejections Correct Acceptances Correct Rejections False Acceptances Fail Pass Cut-off score Job Performance Test scores

6. 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

7. Computational Formula for r X Y XY X Y 2 2 1 4 4 1 16 2 3 6 4 9 3 5 15 9 25 4 7 28 16 49 5 6 30 25 36  X = 15  Y = 25  XY = 83  X = 55  Y = 135 r = = = = = =.80 N  XY – (  X) (  Y) 5(83) – (15)(25)  [N  X – (  X) ][N  Y - (  Y) ]  [5(55) – (15) ][5(135) – (25) 415 – 375 40 40  (275 – 225)(675 – 625)  (50)(50) 50 2 2 2

8. 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

9. 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

10. 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

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 * * * * * * * * * * * * * No Correlation Poor Good FailPass False Rejections Correct Acceptances Correct Rejections False Acceptances

12. 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?

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 * * * * * * * * ** ** * * Poor Good FailPass Correct Acceptances Correct Rejections False Acceptances Significant Correlation False Rejections Effect of lowering cutoff score?