condition mean min max ZT0-3 3.14315 3.14315 3.14315 ZT4-7 2.541395 2.541395 2.541395 ZT8-11 3.5825950000000004 3.5825950000000004 3.5825950000000004 ZT12-15 1.7579250000000002 1.7579250000000002 1.7579250000000002 ZT16-19 1.6394443333333335 1.6394443333333335 1.6394443333333335 ZT20-23 1.62867 1.62867 1.62867