condition mean min max ZT0-3 20.150000000000002 20.150000000000002 20.150000000000002 ZT4-7 1.8 1.8 1.8 ZT8-11 8.3 8.3 8.3 ZT12-15 10.8 10.8 10.8 ZT16-19 6.7 6.7 6.7 ZT20-23 15.850000000000001 15.850000000000001 15.850000000000001