Nature of Research Pt 2

1. Nature of Research Pt 2

2. Definitions:

3. CONSTRUCT: • a fabrication of mind, invisible, unmeasurable.

4. THEORY: • built of constructs, • showing relationships between constructs, • a systematic view of phenomena to explain and/or predict,

5. THEORY: • a network of related constructs, • abstract.

6. Theory consists of: 1. Definitions, explication of constructs. 2. Operational Definitions.

7. Theory consists of: • what we wish to measure, observe or manipulate.

8. Theory consists of: • criteria: must exhaust the definition of the constructs, must be exclusive (not include additional things).

9. Theory consists of:•Explication of constructs. •Operational Definitions. •What we wish to measure, observe or manipulate. •Criteria

10. VARIABLE: Any quality that has more than one value.

11. HYPOTHESIS: Pertaining to the expected relationships among variables.

12. HYPOTHESIS • Must be specific expression of expected answer about relationships among variables. • Interaction of operational definitions, concrete, observable.

13. HYPOTHESIS From testing of the hypothesis one draws inferences which may allow generalization based on the theory.

14. VARIABLES • can be added to sharpen the prediction, provide more explanation.

15. VARIABLES Independent Variable: cause. Dependent Variable: effect.(depends on independent variable)

16. “If [I.V.] then [D.V.].”

17. VARIABLESModerator Variable: moderates the effect of I.V. on the D.V. More than one variable effects outcome.

18. VARIABLESMediated Variable: one that intervenes, allows one variable to act upon another.

19. VALIDITY: Internal • experiment is well controlled, clean. • clearly measures what is concluded. • clearly tests the question asked, the target question. • with no confounding variables

20. VALIDITY: External • artificiality of created situation. • is the conclusion generalizable outside of experimental situation?

21. VALIDITY: External Ex. Piaget studied his own children. Can this be generalizable? A problem of Sample Validity.

22. VALIDITY: External Ex. Study of violent tv watching. Experimental Group watches 3 hrs. of violent tv.

23. VALIDITY: External Ex. Study of violent tv watching. Experimental Group watches 3 hrs. of violent tv. No Control Group. No Choices given. A problem of Extreme Treatment.

24. Measurement Is behavior observed a typical expression of what is to be measured? Ex. What does “time-on-task” measure?

25. CAUSAL RELATIONSHIP • must show statistical relationship • must precede event • must rule out plausible rival hypotheses (PRH)

26. CONTROL GROUP • Ask, What is it designed to control for? • Must be equivalent to experimental group. • Function: to rule out Plausible Rival Hypothesis.

27. Threats to Internal Validity • History If the study has multiple phases, there may be an influence by the early phase on the later phases.

28. Threats to Internal Validity • Testing All participants must be sensitized to the same extent.

29. Threats to Internal Validity • Mortality If dropouts are not equally distributed (randomly) there may be systematic bias.

30. Threats to Internal Validity • Maturation Participants would improve anyway by growing up.

31. HAWTHORNE EFFECT: Effect of attention paid to participants.

32. Threats to Internal Validity are less important in correlational studies than in functional studies. (A correlational study does not show causal relationship.)

33. Regression Toward the Mean Performance varies, and over time values will gravitate to the mean. Highs become lower, and lows become higher.

34. RandomAssignment (Random Selection) Allows for comparability between experimental group and control group. Each individual has the same chance to be in either group. Otherwise there may be bias. (RA) (RS)

35. Sampling Science of choosing representationally from each ethnic, racial, age, class, etc., group. Allows validity with only 1100 polled of 260 million.

36. Precision Difference between groups _______________________ Difference between individuals within group =

37. Precision D B _____ D W Probability (p) =

38. Standard Deviation Size of variability of distribution of individual differences. Mean (x) yields some information, not necessarily meaningful. Range tells more of the story.

39. Standard Deviation A B

40. Standard Deviation

41. X Standard Deviation     6 7 8 9 10 11 12

42. X Standard Deviation         6 7 8 9 10 11 12

43. X Standard Deviation         6 7 8 9 10 11 12

44. X Standard Deviation         6 7 8 9 10 11 12

45. X Standard Deviation         6 7 8 9 10 11 12

46. Statistical Significance “Significance of difference” or, meaningfulness.

47. Statistical Significance Ex. Grp #1–Individual Instruction Grp #2–Group Instruction n=30 in each group (could be 3000) RA, RS Grp. #1 does 3 pts. better on posttest. Is that Significant?

48. Statistical Significance Ex. Grp #1–Individual Instruction Grp #2–Group Instruction n=30 in each group (could be 3000) RA, RS Grp. #1 does 3 pts. better on posttest. Is that Significant? What is the probability that observed differences between the Experimental group and the Control group is due to chance?

49. Probability (p) p = (probability that difference is due to chance)[+ –] .05 95% sure of significance N.B. Level of significance is not level of importance.

50. Probability (p) p = >.05 is the agreed upon standard >.07 is acceptable