condition mean min max ZT0-3 6.050000000000001 6.050000000000001 6.050000000000001 ZT4-7 14.7 14.7 14.7 ZT8-11 14.8 14.8 14.8 ZT12-15 7.4 7.4 7.4 ZT16-19 9.7 9.7 9.7 ZT20-23 15.700000000000001 15.700000000000001 15.700000000000001