condition mean min max ZT0-3 15.850000000000001 15.850000000000001 15.850000000000001 ZT4-7 7.0 7.0 7.0 ZT8-11 10.0 10.0 10.0 ZT12-15 15.799999999999999 15.799999999999999 15.799999999999999 ZT16-19 22.049999999999997 22.049999999999997 22.049999999999997 ZT20-23 14.55 14.55 14.55