condition mean min max ZT0-3 2.985395 2.985395 2.985395 ZT4-7 1.960415 1.960415 1.960415 ZT8-11 1.132805 1.132805 1.132805 ZT12-15 1.3977849999999998 1.3977849999999998 1.3977849999999998 ZT16-19 4.005005 4.005005 4.005005 ZT20-23 3.49474 3.49474 3.49474