From: The concentration of three anti-seizure medications in hair: the effects of hair color, controlling for dose and age
Hair Color
Number of Subjects
Mean VPA Concentration
Standard Deviation
Black
17
9.65
3.39
Brown
7.58
3.30
Blond
3
5.80
1.36
Gray
6.08
2.12
Overall Mean
40
8.22
3.37