condition mean min max ZT0-3 14.149999999999999 14.149999999999999 14.149999999999999 ZT4-7 3.5 3.5 3.5 ZT8-11 3.65 3.65 3.65 ZT12-15 6.1 6.1 6.1 ZT16-19 5.2 5.2 5.2 ZT20-23 3.6500000000000004 3.6500000000000004 3.6500000000000004