1. “Significance and Meaning: Analyzing and Interpreting the Data”
Funding was provided through a Community Engagement Supplement to the Oregon Clinical and Translational Research Institute at Oregon Health & Science University (National Institute of Health/NCRR/NCATS grants UL1TR and ACTRI0601).

2. “What we have here is a failure to communicate.”

4. The following presentation will not make you into a statistician.
Disclaimer
WARNING:
The following presentation will not make you into a statistician.

5. What I hope it will do:
Renew your familiarity with a few basic research concepts and terms
Introduce a few concepts and terms that are commonly used when researchers analyze and try to understand data from studies
Provide a foundation, on which you can build, that may make it easier to work in partnership with academic researchers

6. What We’ll Talk About Today
Review Basic Terms and Concepts
Association (Correlation)
Exposure and Outcome
(Independent & Dependant Variables)
Study Designs
Interpreting Data
Comparing Groups
Sampling from a Population
Statistical Significance

7. What We’ll Talk About Today
Review Basic Terms and Concepts
Association (Correlation)
Exposure and Outcome
(Independent & Dependant Variables)
Study Designs
Interpreting Data
Comparing Groups
Sampling from a Population
Statistical Significance

8. What We’ll Talk About Today
Review Basic Terms and Concepts
Association (Correlation)
Exposure and Outcome
(Independent & Dependant Variables)
Study Designs
Interpreting Data
Comparing Groups
Sampling from a Population
Statistical Significance

9. Association (Correlation)

10. Association (Correlation)
Overweight
Ice Cream Consumption

11. Basic Terms Exposure (Independent variable):
A state of contact with something or any relevant characteristic, habit, or practice that may increase or decrease the likelihood of an outcome
Outcome (Dependent variable):
A disease or other condition that results from an exposure

12. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

13. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

14. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

15. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

16. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

17. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

18. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

19. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

20. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

21. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

22. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

23. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

24. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

25. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

26. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

27. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

28. Independent & Dependent Variables
Cardiovascular Fitness
(Outcome; Dependent Variable)
Aerobic Exercise
(Exposure; Independent Variable)

29. Cardiovascular Fitness
Aerobic Exercise

30. Positive Correlation
Cardiovascular Fitness
Aerobic Exercise

31. Overweight
Aerobic Exercise

32. Negative Correlation
Overweight
Aerobic Exercise

33. Study Design Types (Quantitative)
Descriptive study
Cross-sectional study
Case-Control study
Cohort study
Randomized Trial

34. Four (very) basic stages of studies
Pose a researchable question
Design a study to get data to answer the question
Gather data
Analyze and interpret the data

35. Comparing one group with another…..

36. Which School has the Taller 7th Grade Boys?

37. Which School has the Taller 7th Grade Boys?
Washington Jr. High
Lincoln Jr. High

38. Which School has the Taller 7th Grade Boys?
Washington Jr. High
Lincoln Jr. High
Sample: 1 boy Height = 62” (5 ft, 2 in)

39. Which School has the Taller 7th Grade Boys?
Washington Jr. High
Lincoln Jr. High
Sample: 1 boy Height = 62” (5 ft, 2 in)
Sample: 1 boy Height = 56” (4 ft, 8 in)

40. Which School has the Taller 7th Grade Boys?
Washington Jr. High
Lincoln Jr. High
Sample: 1 boy Height = 62” (5 ft, 2 in)
Sample: 1 boy Height = 56” (4 ft, 8 in)
Conclusion:
7th Grade Boys at Washington Jr. High are Taller

41. Convinced?

42. What more do you want to know ?

43. Which School has the Taller 7th Grade Boys?
Washington Jr. High
Lincoln Jr. High
Sample: 2 boys 1) 62” (5 ft, 2 in) 2) 54” (4 ft, 6 in)
Sample: 2 boys 1) 56” (4 ft, 8 in) 2) 63 “ (5 ft, 3 in)

44. Which School has the Taller 7th Grade Boys?
Washington Jr. High
Lincoln Jr. High
Sample: 2 boys 1) 62” (5 ft, 2 in) 2) 54” (4 ft, 6 in) Mean (average): [ ] ÷ 2 = 116 ÷ 2 = 58” (4 ft, 10 in)
Sample: 2 boys 1) 56” (4 ft, 8 in) 2) 63 “ (5 ft, 3 in) Mean (average): [ ] ÷ 2 = 119 ÷ 2 = 59.5” (4 ft, 11½ in)

45. Which School has the Taller 7th Grade Boys?
Washington Jr. High
Lincoln Jr. High
Sample: 35 boys Mean Height = 58.3” (4 ft, 10 in)
Sample: 35 boys Mean Height = 58.1” (4 ft, 10 in)

46. Height: 7th Grade Boys Washington Junior High

47. Height: 7th Grade Boys Washington Junior High
Sample

48. Height: 7th Grade Boys Lincoln Junior High

49. Height: 7th Grade Boys Lincoln Junior High
Sample

50. Normal Distribution Curve

51. Which School has the Taller 7th Grade Boys?
Washington Jr. High
Lincoln Jr. High
Mean (Average) = 58.4”
Mean (Average) = 58.4”
Sample = 62”
Sample = 56”

52. Who’s Taller: 5th Grade Girls or 7th Grade Girls?

53. Who’s Taller: 5th Grade Girls or 7th Grade Girls?
Sample: 1 girl Height = 58” (4 ft, 10 in)
Sample: 1 girl Height = 56” (4 ft, 8 in)

54. Who’s Taller: 5th Grade Girls or 7th Grade Girls?
Sample: 1 girl Height = 58” (4 ft, 10 in)
Sample: 1 girl Height = 56” (4 ft, 8 in)
Conclusion:
5th Grade Girls are Taller
than 7th Grade Girls

55. Convinced?

56. What more do you want to know ?

57. Height: 5th Grade Girls

58. Height: 5th Grade Girls
Sample

59. Height: 5th Grade Girls
Sample
13 % of the group

60. Height: 7th Grade Girls

61. Height: 7th Grade Girls
Sample

62. Height: 7th Grade Girls
Sample
20 % of the group

63. Height: 5th and 7th Grade Girls
5th Grade Sample = 58”

64. Height: 5th and 7th Grade Girls
7th Grade Sample = 56”
5th Grade Sample = 58”

65. Who’s Taller: 5th Grade Girls or 7th Grade Girls?
Sample: 30 girls Mean Height = 54” (4 ft, 6 in)
Sample: 30 girls Mean Height = 58” (4 ft, 10 in)
Conclusion:
7th Grade Girls are Taller
than 5th Grade Girls

66. Height: 5th and 7th Grade Girls
7th Grade Mean = 58.8”
5th Grade Mean = 54.5”
7th Grade Sample = 56”
5th Grade Sample = 58”

67. When do we feel comfortable that our findings closely represent the real situation and are not just due to chance?

68. Statistical Significance
What does it mean ?

72. Is the coin fair?

74. Probabilities of Consecutive Heads
1 Head 1 in (50%) 2 Heads 1 in (25%) 3 Heads 1 in (12.5%) 4 Heads 1 in (6.3%) 5 Heads 1 in (3.1%) 6 Heads 1 in (1.6%) 7 Heads 1 in (0.8%)

75. Statistical Significance
The probability that the result is due to chance is low.

76. Statistical Significance
The probability that the result is due to chance is low. How low ?

77. Statistical Significance
The probability that the result is due to chance is low. How low ? We choose….usually less than 5 %. (i.e., “p-value” < 0.05)

78. Statistical Significance
What does it mean ?

79. Statistical Significance
What does it mean ? That the findings are “true” ?

80. Statistical Significance
What does it mean ? That the findings are “true” ?

81. Statistical Significance
What does it mean ? That the findings are “true” ? That the study is of better quality ?

82. Statistical Significance
What does it mean ? That the findings are “true” ? That the study is of better quality ?

83. Statistical Significance
What does it mean ? That the findings are “true” ? That the study is of better quality ? That the findings are more important?

84. Statistical Significance
What does it mean ? That the findings are “true” ? That the study is of better quality ? That the findings are more important?

85. What kind of Significance ?
A program to increase exercise in kids:
4000 participants
(2000 intervention; 2000 control)
At baseline: Each group 60 min/week
After intervention:
- Intervention group: 62 min/week
- Control group: 60 min/week
- P-value = 0.03 (3 %)

86. Some Implications for Study Design
Need to understand how large or small of a difference is important to detect
Need to know how many study participants to include

88. Questions? Comments?