condition mean min max ZT0-3 7.5 7.5 7.5 ZT4-7 4.8 4.8 4.8 ZT8-11 5.800000000000001 5.800000000000001 5.800000000000001 ZT12-15 6.6 6.6 6.6 ZT16-19 7.15 7.15 7.15 ZT20-23 5.15 5.15 5.15