condition mean min max ZT0-3 11.923867 11.923867 11.923867 ZT4-7 11.4968375 11.4968375 11.4968375 ZT8-11 11.479124500000001 11.479124500000001 11.479124500000001 ZT12-15 11.237104500000001 11.237104500000001 11.237104500000001 ZT16-19 12.28688 12.28688 12.28688 ZT20-23 17.0919235 17.0919235 17.0919235