Table 4 

Type I error associated with the test for association between LV ejection fraction and the 96 AIMs 

Control variable 
Average Type I error 
Standard error 
Observed minimum Type I error 
Observed maximum Type I error 


Individual admixture estimates 
0.038 
0.0058 
0.021 
0.042 


Principal components 
0.048 
0.007 
0.021 
0.052 


Selfreported Ethnicity 
0.042 
0.004 
0.031 
0.053 


Ignoring confounding 
0.705 
0.009 
0.694 
0.737 


Note that when the confounding effect is ignored the type I error is about 14 times the nominal rate. However, controlling for Selfreported ethnicity alone in this case is sufficient to keep the type I error rate at its nominal value. 

Divers et al. BMC Genetics 2011 12:28 doi:10.1186/147121561228 