condition mean min max ZT0-3 4.85 4.85 4.85 ZT4-7 6.2 6.2 6.2 ZT8-11 7.199999999999999 7.199999999999999 7.199999999999999 ZT12-15 7.9 7.9 7.9 ZT16-19 7.75 7.75 7.75 ZT20-23 7.6000000000000005 7.6000000000000005 7.6000000000000005