Figure 3. Box-plot analysis of the signal ratios obtained with genomic DNA of 30 Mycobacterium ulcerans strains identifying plasmids yielding outlier signals. Shown is the signal ratio in comparison with the African reference strain Agy99. The median of the ratios obtained is represented by the line in the center of the rectangular box. The 2 ends of the rectangles represent the upper quartile (UQ), which corresponds to the 75th percentile, and the lower quartile (LQ), which corresponds to the 25th percentile. The interquartile (IQ) is equal to UQ – LQ. The other 2 values shown are the maximum and minimum value of the data set: U1 = UQ + 1.5IQ; L1 = LQ – 1.5IQ. Double slashes represent discontinued range on the y-axis, values of the outliers beyond 100 in brackets. DRC, Democratic Republic of Congo; Aust., Australia; C. d’Iv, Côte d’Ivoire. PNG, Papua New Guinea.