Skip to main content

Table 2 Phase I and phase II sample power.

From: Genetic factors leading to chronic Epstein-Barr virus infection and nasopharyngeal carcinoma in South East China: Study design, methods and feasibility

    

Phase I

Phase II

All

    

Case/control

Power

Case/control

Power

Case/control

Power

NPC+vs IgA+

   

350/288

 

1024/1009

 

1374/1297

 
 

OR

0.75

1.5

 

17%

 

64%

 

79%

  

0.50

2.0

 

62%

 

> 99%

 

> 99%

  

0.33

3.0

 

98%

 

> 99%

 

> 99%

IgA+ vs IgA-

   

288/346

 

1009/1022

 

1297/1368

 
 

OR

0.75

1.5

 

18%

 

64%

 

79%

  

0.50

2.0

 

64%

 

99%

 

> 99%

  

0.33

3.0

 

99%

 

> 99%

 

> 99%

NPC+/IgA+ vs IgA-

  

638/346

 

2033/1022

 

2671/1368

 
 

OR

0.75

1.5

 

25%

 

77%

 

90%

  

0.50

2.0

 

78%

 

> 99%

 

> 99%

  

0.33

3.0

 

> 99%

 

> 99%

 

> 99%

  1. Note. Allele frequency = 10 per cent; Type 1 error = 1 per cent.
  2. Power calculated for a 10% allele frequency, dominant genetic model and a p value of ≤ 0.01 for given case and control numbers using a two-tailed test. For example, with the Phase I cases/controls available, we would discover a genetic association of strength OR = 1.5, only 14% of the time, but a stronger gene (OR = 3.0) would be detected 96% of the time with available patient numbers.
  3. Abbreviations: IgA, immunoglobulin A; NPC, nasopharyngeal carcinoma.
Back to article page

Human Genomics

ISSN: 1479-7364