Remember

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# Remember - PowerPoint PPT Presentation

## Remember

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##### Presentation Transcript

1. Remember • You were asked to determine the effects of both college major (psychology, sociology, and biology) and gender (male and female) on class attendance

2. Sociology Psychology Biology

3. Simple Effects • The effect of one factor at one level on the other factor. • Use to “tease apart” a significant interaction • You wonder if college major has an effect on class attendance for just females? • You wonder if male and female psychology students differ in their class attendance?

4. Sociology Psychology Biology

5. Sociology Psychology Biology

6. Sociology Psychology Biology

7. Sociology Psychology Biology

8. Sociology Psychology Biology

9. Sociology Psychology Biology

10. Simple Effects • Why not just do 5 new analyses • 2 ANOVAs • 3 Independent Samples t-tests • You will lose df! • Type I error problem still exists

11. Sociology Psychology Biology

12. Are these means different?

13. Simple Effects • SS Major at Female • Represents the SS deviations of the treatment means around the Female mean • Its multiplied by n to give an estimate of the population variance (Central limit theorem) • Same formula as SSbetween in the one-way

14. SS M at Female = 3*((2.67 – 1.78)2 + (1.00 – 1.78)2 + (1.67 – 1.78)2 = 4.23

15. Note

16. Sociology Psychology Biology

17. Are these means different?

18. Simple Effects • SS Major at Male • Same formula as SSbetween in the one-way

19. SS M at Male = 3*((3.67 – 2.33)2 + (3.00 – 2.33)2 + (0.33 – 2.33)2 = 18.71

20. Sociology Psychology Biology

21. Are these means different?

22. Simple Effects • SS Gender at Socio • Same formula as SSbetween in the one-way

23. Sociology Psychology Biology

24. Are these means different?

25. Simple Effects • SS Gender at Psych • Same formula as SSbetween in the one-way

26. Sociology Psychology Biology

27. Are these means different?

28. Simple Effects • SS Gender at Bio • Same formula as SSbetween in the one-way

29. SS G at Bio = 3*((1.67 – 1.00)2 + (0.33 – 1.00)2 = 2.69

30. Overall ANOVA

31. Simple Effects

32. Simple Effects

33. Simple Effects dfA (Gender) = a – 1 dfB (Major) = b – 1

34. Simple Effects Compute MS

35. Simple Effects Compute F

36. F critical (1, 12) = 4.75 F critical B (2, 12) = 3.89 Simple Effects

37. Sociology Psychology Biology

38. Practice • ANOVA is from exercise 13.5 • 1) Interpret the ANOVA results • 2) Plot the cell means • 3) Compute an entire set of simple effects