condition mean min max ZT0-3 16.150000000000002 16.150000000000002 16.150000000000002 ZT4-7 2.4 2.4 2.4 ZT8-11 3.5 3.5 3.5 ZT12-15 9.55 9.55 9.55 ZT16-19 8.899999999999999 8.899999999999999 8.899999999999999 ZT20-23 14.35 14.35 14.35