Fig. 2
From: Effects of smoking cessation on biological monitoring markers in urine
Changes in urinary tobacco exposure biomarker levels by smoking cessation. Horizontal bars indicate medians. Group 1: The subjects who participated in the quit-smoking program for 2 weeks (n = 42, Wilcoxon signed-rank test). Group 2: The subjects who completed the quit-smoking program (n = 18, Friedman’s test followed by Dunn’s multiple comparisons test). ** p < 0.01. Individual changes in biomarkers are indicated by the lines in (d – f)