condition mean min max ZT0-3 10.06469 10.06469 10.06469 ZT4-7 6.969235 6.969235 6.969235 ZT8-11 4.176325 4.176325 4.176325 ZT12-15 2.774685 2.774685 2.774685 ZT16-19 6.3573 6.3573 6.3573 ZT20-23 7.87424 7.87424 7.87424