condition mean min max ZT0-3 5.2067516666666664 3.5481749999999996 6.72384 ZT4-7 4.9104849999999995 4.9104849999999995 4.9104849999999995 ZT8-11 5.96427 5.96427 5.96427 ZT12-15 8.01477 7.4826250000000005 8.546915 ZT16-19 11.108585000000001 11.108585000000001 11.108585000000001 ZT20-23 13.25515 13.25515 13.25515