Table 4
Mean rank of scores by number of previous experiences with nitrous oxide
Phase
1a
1b
2
3a
3b
4
Total
0
47.8
50.9
44.7
47.7
46.1
47.6
50.0
1–5
43.7
41.6
44.5
41.5
42.7
43.4
40.5
6–10
43.2
39.5
47.9
45.3
47.2
43.8
42.3
p value
0.652
0.136
0.777
0.627
0.603
0.695
0.288
p < 0.05.