. Author manuscript; available in PMC: 2010 Jan 28.

Published in final edited form as: Neuropsychopharmacology. 2007 Nov 28;33(9):2139–2147. doi: 10.1038/sj.npp.1301623

Table 2.

F-Values and Degrees of Freedom for Analyses of Responses During Acquisition (Experiment 2)

	Nicotine-seeking^a		VS-seeking^b

	df	F	df	F
FR 1 (sessions 1–12)
Group	3, 33	4.71^**	3, 29	4.73^**
Session	11, 363	8.26^**	11, 319	6.08^**
Group × session	33, 363	2.27^**	33, 319	5.33^**
FR 2 (sessions 13–22)
Group	3, 33	21.72^**	3, 29	10.24^**
Session	9, 297	1.33	9, 261	1.98^*
Group × session	27, 297	0.53	27, 261	1.02

^**

p ≤ 0.01,

p ≤ 0.05.

Includes responses that result in nicotine infusion (2-lever, NIC+VS, and NIC-only groups) or saline (SAL-only group).

Includes responses that result in VS presentation (2-lever, NIC+VS, and VS-only groups) or saline (SAL-only group). The SAL-only group is included in both sets of analyses as a ‘nonreinforcement’ control.