condition mean min max ZT0-3 4.4 4.4 4.4 ZT4-7 5.9 5.9 5.9 ZT8-11 2.55 2.55 2.55 ZT12-15 4.4 4.4 4.4 ZT16-19 1.2999999999999998 1.2999999999999998 1.2999999999999998 ZT20-23 18.9 18.9 18.9