condition mean min max ZT0-3 8.20071 8.165925 8.235495 ZT4-7 9.0486 9.0486 9.0486 ZT8-11 7.4162300000000005 7.4162300000000005 7.4162300000000005 ZT12-15 0 0 0 ZT16-19 9.04617 9.04617 9.04617 ZT20-23 8.174365 8.174365 8.174365