condition mean min max ZT0-3 2.65 2.65 2.65 ZT4-7 4.6 4.6 4.6 ZT8-11 3.8 3.8 3.8 ZT12-15 6.199999999999999 6.199999999999999 6.199999999999999 ZT16-19 6.15 6.15 6.15 ZT20-23 3.15 3.15 3.15