Influence of high- and low-volume liver surgery in gallbladder carcinoma

Figure 4 Medians of liver resections according to the 3 volume groups (Tis-T4 carcinomas/all patients). The middle bar of the box plot represents the median, whereas the lower and upper bars of the box represent the 25^th and 75^th quartiles, respectively. The dots and asterisks represent outliers. The boxplot-test of all patients/volume-centers shows that the median of liver resection at high-volume centers was 60, that at mid-volume centers was 28 and that at low-volume centers was 5.