Distribution of BLV-infected farms classified by seroprevalence (n = 90). Seroprevalence on infected farms at the 25th, 50th (median), and 75th percentiles was 17.1%, 48.1%, and 68.5%, respectively. Visual inspection of this histogram and the Shapiro--Wilk test confirmed that seroprevalence was not normally distributed (p < 0.002).
Kobayashi et al. BMC Veterinary Research 2010 6:1 doi:10.1186/1746-6148-6-1