condition mean min max ZT0-3 4.8 4.8 4.8 ZT4-7 2.9 2.9 2.9 ZT8-11 6.800000000000001 6.800000000000001 6.800000000000001 ZT12-15 4.8 4.8 4.8 ZT16-19 10.6 10.6 10.6 ZT20-23 6.3 6.3 6.3