Table 2. Mean ± SD of retention values and the results of one-way ANOVA and pairwise comparisons (LSD) tests of the studied groups .

Group	Retention (N)	Ln (retention)*	P(one-way ANOVA)	Significant pairwise comparisons (LSD P value)
1	46.88 ± 10.16	3.82 ± 0.24		3 vs 1 (0.016)
2	46.31 ± 9.06	3.82 ± 0.20	0.019	3 vs 2 (0.015)
3	65.30 ± 18.85	4.13 ± 0.33		4 vs 1 (0.038)
4	62.25 ± 17.92	4.09 ± 0.31		4 vs 2 (0.034)
*Retention was changed to natural logarithm (Ln) to obtain homogeneity of variances in one-way ANOVA.