Fig. 1
From: Impact of quality certification of multidisciplinary head and neck tumor centers
Comparison of general characteristics from 2008–2012 to 2013–2017. a Number of cases per year was tested parametrically with student’s t-test. Data are shown as mean ± SEM. b The average age was tested nonparametrically with Mann-Whitney U test. Data are shown as mean ± SEM. c Gender distribution changes was assessed with Fisher’s exact test. Data are shown as absolute count