condition mean min max ZT0-3 2.8059616666666667 2.479415 2.9749 ZT4-7 3.3690350000000002 3.3690350000000002 3.3690350000000002 ZT8-11 2.596875 2.596875 2.596875 ZT12-15 4.79922 3.8449400000000002 5.7535 ZT16-19 3.09262 3.09262 3.09262 ZT20-23 3.1299650000000003 3.1299650000000003 3.1299650000000003