condition mean min max ZT0-3 7.7 7.7 7.7 ZT4-7 7.4 7.4 7.4 ZT8-11 5.05 5.05 5.05 ZT12-15 5.199999999999999 5.199999999999999 5.199999999999999 ZT16-19 6.85 6.85 6.85 ZT20-23 9.25 9.25 9.25