condition mean min max ZT0-3 4.578101666666666 3.63826 5.082095 ZT4-7 2.804755 2.804755 2.804755 ZT8-11 3.36158 3.36158 3.36158 ZT12-15 5.5615475 4.9024149999999995 6.22068 ZT16-19 7.339715 7.339715 7.339715 ZT20-23 7.06401 7.06401 7.06401