. Author manuscript; available in PMC: 2014 Nov 1.

Published in final edited form as: Psychopharmacology (Berl). 2013 Jun 10;230(2):10.1007/s00213-013-3150-5. doi: 10.1007/s00213-013-3150-5

Table 2.

Plasma nicotine values (n/mL) at baseline, after three days of use of a cigarette filter that removed 50% of nicotine and tar from cigarettes (“post restriction”), and their difference (N=166).

	Baseline	Post restriction	Difference
Mean	16.4	12.5	−3.7
SD	6.69	7.56	7.77
SE Mean	0.50	0.58	0.60
95% CI Mean	(17.3, 15.4)	(13.6, 11.3)	(−2.6, −4.9)
t-ratio	---	---	−6.25
DF	---	---	167
Prob > \|t\|	---	---	<.0001