1. Population and Sample Means Slide 12.1A

2. Population and Sample Means Slide 12.1

3. Mean Advantages and Disadvantages Advantages commonly understood all data have one descriptive mean Disadvantages  extreme scores distort mean  tedious if computed by hand Slide 12.2

4. SAMPLE DATA and the Mean 135579135579 Slide 12.3A

5. SAMPLE DATA and the Mean 135579135579 Slide 12.3B

6. SAMPLE DATA and the Mean 135579135579 Slide 12.3C

7. SAMPLE DATA and the Mean 135579135579 Slide 12.3D

8. SAMPLE DATA and the Mean 135579135579 Slide 12.3

9. Median Advantages and Disadvantages Advantages not distorted by extreme scores useful to detect deviations from normal distributions Disadvantages  may be tedious to find by hand Slide 12.4

10. Mode Advantages and Disadvantages Advantages not distorted by extreme scores useful for both qualitative and quantitative data Disadvantages  data may not have a true mode  useless if many modes Slide 12.5

11. Assessing Dispersion by Looking at Spread 258258 Data Mean = 5 Slide 12.6A

12. Assessing Dispersion by Looking at Spread 258258 Data Mean = 5 How far from the mean are the data? Slide 12.6

13. Starting to Assess the Variance 258258 - 5 = - 3 = 0 = 3 Slide 12.7

14. = - 3 = 0 = 3 A Formula to Assess the Variance 258258 - 5 9 0 9 Slide 12.8A

15. = - 3 = 0 = 3 A Formula to Assess the Variance 258258 - 5 9 0 9 = 18 Slide 12.8B

16. = - 3 = 0 = 3 A Formula to Assess the Variance 258258 - 5 9 0 9 = 18 Slide 12.8C

17. = - 3 = 0 = 3 A Formula to Assess the Variance 258258 - 5 9 0 9 = 18 THE VARIANCE Slide 12.8

18. Sample and Population Standard Deviations Slide 12.9A

19. Sample and Population Standard Deviations Slide 12.9

20. SAMPLE AND POPULATION TERMS SamplePopulation Slide 12.10A

21. SAMPLE AND POPULATION TERMS SamplePopulation Mean Slide 12.10B

22. SAMPLE AND POPULATION TERMS SamplePopulation Mean Variance Slide 12.10C

23. SAMPLE AND POPULATION TERMS SamplePopulation Mean Variance Standard Deviation Slide 12.10

24. Standard Normal Curve = 0 = 1 - 3  + 3  Slide 12.11

25. z Scores when Data Do Not Already Have a Mean of 0 and a Standard Deviation of 1 Slide 12.12A

26. z Scores when Data Do Not Already Have a Mean of 0 and a Standard Deviation of 1 or Slide 12.12

27. Areas under the Standard Normal Curve 0 Slide 12.13 z = -1.67 z = 1

28. Areas under the Standard Normal Curve 0 Slide 12.14 z = -1.75z = 1.75

29. Areas under the Standard Normal Curve 0 z = 1 Slide 12.15

30. Correlation Example 1234512345 3475634756 Speaking Skill X Writing Skill Y Slide 12.16A

31. Correlation Example 1234512345 3475634756 Speaking Skill X Writing Skill Y Slide 12.16B - 2 - 1 0 1 2 - 2 - 1 2 0 1

32. Correlation Example 1234512345 3475634756 Speaking Skill X Writing Skill Y Slide 12.16C - 2 - 1 0 1 2 - 2 - 1 2 0 1 * 4 1 0 2

33. Correlation Example 1234512345 3475634756 Speaking Skill X Writing Skill Y Slide 12.16D - 2 - 1 0 1 2 - 2 - 1 2 0 1 * 4 1 0 2 = 7

34. Correlation Example 1234512345 3475634756 Speaking Skill X Writing Skill Y Slide 12.16 - 2 - 1 0 1 2 - 2 - 1 2 0 1 * 4 1 0 2 = 7 n-1 = 4

35. Correlation Computation Slide 12.17A

36. Correlation Computation Slide 12.17B

37. Correlation Computation Slide 12.17C

38. Correlation Computation Slide 12.17D

39. Correlation Computation Slide 12.17