Learning behavior in rat offspring after in utero and lactational exposure to either TCDD or PCB126

Table 3 Results of statistical analysis of response rates (numbers of response per minute) in the FR20 and DRL20s components, and reward rate (number of reward per minute) in the DRL20s component analyzed by the one-way ANOVA with repeated measures

Factor	df	Fixed ratio		Differential reinforcement of low rates
		Response/min		Response/min		Reward/min
		F	P	F	P	F	P
Phase	2,200	5.56	0.005	27.38	0.000	91.73	0.000
Chemical	1,100	2.01	0.16	2.16	0.15	2.80	0.097
Dose	3,100	4.41	0.006	2.45	0.068	1.59	0.20
Sex	1,100	2.42	0.12	0.27	0.60	0.12	0.91
Chemical × dose	1,100	1.40	0.25	0.95	0.42	1.12	0.35
Chemical × dose × phase	1,100	0.40	0.99	2.10	0.061	0.93	0.47
Chemical × dose × sex	1,100	0.63	0.60	0.18	0.91	0.25	0.86

df degrees of freedom, F F-value, p p-value. Chemical (TCDD or PCB), dose (low, medium or high) and sex (male or female) were treated as between-subject factors, and phase (1, 2 and 3) was treated as a within-subject factor for repeated measures ANOVA. Because all of the three indices had a normal distribution, they were subjected to logarithmic transformation. Differences at p < 0.05 were considered significant

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