Table 4.

Pre-, post- and difference scores on N2 in all conditions (n = 20, mean ± SEM)

	Control	Placebo	Caffeine	Active placebo
Pre	−9.5 ± 1.9	−11.2 ± 1.9	−10.9 ± 1.9	−10.4 ± 2.0
Post	−6.8 ± 1.9	−9..0 ± 1.8	−7.4 ± 1.5	−6.5 ± 1.4
Difference	−2.7 ± 1.4	−2.2 ± 1.0	−3.5 ± 0.8	−3.9 ± 1.0