condition mean min max ZT0-3 6.199999999999999 6.199999999999999 6.199999999999999 ZT4-7 6.3 6.3 6.3 ZT8-11 31.0 31.0 31.0 ZT12-15 20.6 20.6 20.6 ZT16-19 5.6 5.6 5.6 ZT20-23 28.5 28.5 28.5