highly significantP < 0.001
However, when the cups offered 10 3 ppm p -cresol, the group effect was highly significant (P < 0.001, two-way ANOVA): 10 3 ppm was deterrent in comparison with water (P < 0.001, post hoc pairwise t -test with Holm correction) and also in comparison with 10 1 ppm (P = 0.015, post hoc pairwise t -test with Holm correction), while 10 2 , 10 1 ppm were not significantly different from water or each other (Figure 6 b).