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Table 3 Statistical power based on one-way ANOVA for the 3 primary response variables testing at 0.05 level of significance using SDs from preliminary data and the literature

From: Effect of spinal manipulation on sensorimotor functions in back pain patients: study protocol for a randomised controlled trial

  

Power A

Power B

Response Variable

Contrasts*

Contrasts*

Sway Speed

Solid

>99%

>99%

 

Foam

86

80

Mean Sway X

Solid

76-94

69-90

 

Foam

64-73

58-67

Mean Sway Y

Solid

88-95

83-92

 

Foam

21-34

18-30

  1. Effect sizes: Sway Speed: 4 mm/sec; Mean Sway X: 1 mm; Mean Sway Y: 0.5 mm [47, 94] Power A is determined for n = 73 per group for the immediate changes in the pre- to post-treatment measurements at the first treatment. Power B is determined for n = 63 per group for the changes in the pre-treatment variables at the first treatment and at week 2.
  2. *Two 1 degree of freedom contrasts to test mean differences of HVLA-SM vs Sham Control and LVVA-SM vs Sham Control.
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ISSN: 1745-6215