condition mean min max ZT0-3 15.299999999999999 15.299999999999999 15.299999999999999 ZT4-7 17.6 17.6 17.6 ZT8-11 14.2 14.2 14.2 ZT12-15 14.35 14.35 14.35 ZT16-19 7.7 7.7 7.7 ZT20-23 1.9500000000000002 1.9500000000000002 1.9500000000000002