condition mean min max ZT0-3 16.450000000000003 16.450000000000003 16.450000000000003 ZT4-7 4.2 4.2 4.2 ZT8-11 8.65 8.65 8.65 ZT12-15 15.25 15.25 15.25 ZT16-19 9.45 9.45 9.45 ZT20-23 14.0 14.0 14.0