condition mean min max ZT0-3 3.8707483333333332 3.38245 4.2597249999999995 ZT4-7 2.13301 2.13301 2.13301 ZT8-11 2.016675 2.016675 2.016675 ZT12-15 3.200695 3.0719250000000002 3.329465 ZT16-19 3.235335 3.235335 3.235335 ZT20-23 3.958485 3.958485 3.958485