condition mean min max ZT0-3 5.85 5.85 5.85 ZT4-7 12.8 12.8 12.8 ZT8-11 13.8 13.8 13.8 ZT12-15 5.6000000000000005 5.6000000000000005 5.6000000000000005 ZT16-19 7.15 7.15 7.15 ZT20-23 1.2 1.2 1.2