condition mean min max ZT0-3 7.5 7.5 7.5 ZT4-7 40.9 40.9 40.9 ZT8-11 14.700000000000001 14.700000000000001 14.700000000000001 ZT12-15 14.5 14.5 14.5 ZT16-19 23.150000000000002 23.150000000000002 23.150000000000002 ZT20-23 18.650000000000002 18.650000000000002 18.650000000000002