condition mean min max ZT0-3 2.25731 2.005565 2.41893 ZT4-7 2.324655 2.324655 2.324655 ZT8-11 1.78878 1.78878 1.78878 ZT12-15 2.7150325 2.10335 3.326715 ZT16-19 2.1606500000000004 2.1606500000000004 2.1606500000000004 ZT20-23 3.138625 3.138625 3.138625