condition mean min max ZT0-3 3.1999999999999997 3.1999999999999997 3.1999999999999997 ZT4-7 13.3 13.3 13.3 ZT8-11 3.65 3.65 3.65 ZT12-15 6.85 6.85 6.85 ZT16-19 19.55 19.55 19.55 ZT20-23 18.4 18.4 18.4