condition mean min max ZT0-3 14.85 14.85 14.85 ZT4-7 7.7 7.7 7.7 ZT8-11 7.7 7.7 7.7 ZT12-15 12.8 12.8 12.8 ZT16-19 6.199999999999999 6.199999999999999 6.199999999999999 ZT20-23 8.9 8.9 8.9