condition mean min max ZT0-3 3.781695 3.781695 3.781695 ZT4-7 3.17561 3.17561 3.17561 ZT8-11 3.18133 3.18133 3.18133 ZT12-15 2.53744 2.53744 2.53744 ZT16-19 4.2034400000000005 4.2034400000000005 4.2034400000000005 ZT20-23 2.9084849999999998 2.9084849999999998 2.9084849999999998