condition mean min max ZT0-3 3.8 3.8 3.8 ZT4-7 5.3 5.3 5.3 ZT8-11 9.15 9.15 9.15 ZT12-15 7.800000000000001 7.800000000000001 7.800000000000001 ZT16-19 4.4 4.4 4.4 ZT20-23 9.5 9.5 9.5