Skip to main content
. 2025 May 13;166(9):e212–e232. doi: 10.1097/j.pain.0000000000003606

Table 3.

Statistical analysis using repeated measures 2-way analysis of variance or 3-way analysis of variance of remifentanil during acquisition of opioid intravenous self-administration, where data are presented in Figure 3.

Figure 2 F (DFn, DFd) P
Remifentanil IVSA
 Figure 3B Reinforcers Time F (3, 81) = 2.581 P = 0.0592
Pain F (1, 27) = 6.568 P = 0.0163*
Time × pain F (3, 81) = 0.6613 P = 0.5782
 Figure 3C Nose pokes Time F (3, 216) = 3.738 P = 0.0120*
Pain F (1, 216) = 5.271 P = 0.0226*
Nose poke F (1, 216) = 30.16 P < 0.0001****
Time × poke F (3, 216) = 0.4089 P = 0.7468
Time × pain F (3, 216) = 0.1054 P = 0.9569
Poke × pain F (1, 216) = 10.03 P = 0.0018**
Time × poke × pain F (3, 216) = 0.1837 P = 0.9074
 Figure 3D Discrimination index Time F (3, 78) = 0.2823 P = 0.8381
Pain F (1, 26) = 5.687 P = 0.0247*
Time × pain F (3, 78) = 0.1187 P = 0.9489
 Figure 3G
Day 1
Cumulative reinforcers Time × pain F (120, 3240) = 2.796 P < 0.0001****
Time F (1.819, 49.10) = 51.26 P < 0.0001
Pain F (1, 27) = 3.071 P = 0.0910
AUC t = 1.753, df = 27 P = 0.0910
 Figure 3G
Day 2
Cumulative reinforcers Time × pain F (120, 3120) = 3.883 P < 0.0001****
Time F (1.244, 32.35) = 51.42 P < 0.0001****
Pain F (1, 26) = 5.814 P = 0.0233*
AUC t = 2.411, df = 26 P = 0.0233*
 Figure 3G
Day 3
Cumulative reinforcers Time × pain F (120, 3120) = 6.429 P < 0.0001****
Time F (1.413, 36.74) = 46.72 P < 0.0001****
Pain F (1, 26) = 10.49 P = 0.0033**
AUC t = 3.239, df = 26 P = 0.0033**
 Figure 3G
Day 4
Cumulative reinforcers Time × pain F (120, 3120) = 2.247 P < 0.0001****
Time F (1.250, 32.50) = 50.43 P < 0.0001****
Pain F (1, 26) = 3.472 P = 0.0737
AUC t = 1.863, df = 26 P = 0.0737
 Figure 3G
Day 5
Cumulative reinforcers Time × pain F (120, 2880) = 6.219 P < 0.0001****
Time F (1.444, 34.67) = 60.29 P < 0.0001****
Pain F (1, 24) = 8.333 P = 0.0081**
AUC t = 2.934, df = 23 P = 0.0075**
 Figure 3H Cumulative reinforcers by day and sex Male day 1 t = 9.343, df = 8 P < 0.0001****
Male day 2 t = 5.239, df = 8 P = 0.0008***
Male day 3 t = 5.360, df = 8 P = 0.0007***
Male day 4 t = 3.827, df = 8 P = 0.0050**
Male day 5 t = 8.418, df = 7 P < 0.0001****
Female day 1 t = 0.3854, df = 5 P = 0.7158
Female day 2 t = 2.676, df = 5 P = 0.0440*
Female day 3 t = 12.27, df = 5 P < 0.0001****
Female day 4 t = 1.355, df = 5 P = 0.2336
Female day 5 t = 3.625, df = 5 P = 0.0151*

A 1-sample t test and Wilcoxon test were used for the cumulative reinforcers being different than theoretical value of zero. P values are provided for each of the factors (time, pain, and if there was an interaction) for active and inactive nose pokes, and number of reinforcers earned. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.

AUC, area under the curve; IVSA, intravenous self-administration.