condition mean min max ZT0-3 12.406134 12.406134 12.406134 ZT4-7 13.261811999999999 13.261811999999999 13.261811999999999 ZT8-11 10.9868725 10.9868725 10.9868725 ZT12-15 11.7023455 11.7023455 11.7023455 ZT16-19 11.8700095 11.8700095 11.8700095 ZT20-23 11.3156845 11.3156845 11.3156845