condition mean min max ZT0-3 18.450000000000003 18.450000000000003 18.450000000000003 ZT4-7 17.1 17.1 17.1 ZT8-11 13.0 13.0 13.0 ZT12-15 11.0 11.0 11.0 ZT16-19 24.950000000000003 24.950000000000003 24.950000000000003 ZT20-23 16.35 16.35 16.35