condition mean min max ZT0-3 5.199999999999999 5.199999999999999 5.199999999999999 ZT4-7 11.6 11.6 11.6 ZT8-11 2.15 2.15 2.15 ZT12-15 7.15 7.15 7.15 ZT16-19 29.150000000000002 29.150000000000002 29.150000000000002 ZT20-23 3.9 3.9 3.9