condition mean min max ZT0-3 9.4 9.4 9.4 ZT4-7 4.9 4.9 4.9 ZT8-11 5.800000000000001 5.800000000000001 5.800000000000001 ZT12-15 26.650000000000002 26.650000000000002 26.650000000000002 ZT16-19 6.8 6.8 6.8 ZT20-23 6.25 6.25 6.25