condition mean min max ZT0-3 16.839659 16.839659 16.839659 ZT4-7 12.8400175 12.8400175 12.8400175 ZT8-11 10.810006999999999 10.810006999999999 10.810006999999999 ZT12-15 15.844430500000001 15.844430500000001 15.844430500000001 ZT16-19 13.1426235 13.1426235 13.1426235 ZT20-23 16.817666 16.817666 16.817666