condition mean min max ZT0-3 2.6563266666666667 1.68077 3.66588 ZT4-7 3.0968 3.0968 3.0968 ZT8-11 2.12432 2.12432 2.12432 ZT12-15 3.9720924999999996 3.7052449999999997 4.2389399999999995 ZT16-19 3.5157249999999998 3.5157249999999998 3.5157249999999998 ZT20-23 3.8459950000000003 3.8459950000000003 3.8459950000000003