condition mean min max ZT0-3 7.199999999999999 7.199999999999999 7.199999999999999 ZT4-7 23.8 23.8 23.8 ZT8-11 7.4 7.4 7.4 ZT12-15 33.75 33.75 33.75 ZT16-19 31.1 31.1 31.1 ZT20-23 21.15 21.15 21.15