condition mean min max ZT0-3 8.4 8.4 8.4 ZT4-7 5.7 5.7 5.7 ZT8-11 18.650000000000002 18.650000000000002 18.650000000000002 ZT12-15 13.85 13.85 13.85 ZT16-19 16.3 16.3 16.3 ZT20-23 6.4 6.4 6.4