condition mean min max ZT0-3 4.0087633333333335 2.7131100000000004 4.827465 ZT4-7 3.781375 3.781375 3.781375 ZT8-11 4.1974350000000005 4.1974350000000005 4.1974350000000005 ZT12-15 5.2159025 5.002330000000001 5.429475 ZT16-19 5.2760549999999995 5.2760549999999995 5.2760549999999995 ZT20-23 5.038869999999999 5.038869999999999 5.038869999999999