Sorce of caffeine

Mean

Standard deviation

Coffee

158.4

133.1

Soda (coke)

24.7

30.7

Chocolate

22.5

37.1

Green tea

19.8

27.1

Black tea

17.4

23.9

Other types of soda

16.3

26.1

Medicine

5.5

10.1

Cocoa powder

1.9

1.8

Other

10.2

12.0