condition mean min max ZT0-3 22.77515 19.2842 26.8215 ZT4-7 21.8291 21.8291 21.8291 ZT8-11 16.8018 16.8018 16.8018 ZT12-15 27.0258 26.64385 27.40775 ZT16-19 21.811700000000002 21.811700000000002 21.811700000000002 ZT20-23 27.14725 27.14725 27.14725