condition mean min max ZT0-3 8.350000000000001 8.350000000000001 8.350000000000001 ZT4-7 7.3 7.3 7.3 ZT8-11 29.599999999999998 29.599999999999998 29.599999999999998 ZT12-15 23.799999999999997 23.799999999999997 23.799999999999997 ZT16-19 13.85 13.85 13.85 ZT20-23 39.300000000000004 39.300000000000004 39.300000000000004