condition mean min max ZT0-3 1.907645 1.907645 1.907645 ZT4-7 2.15162 2.15162 2.15162 ZT8-11 1.2040069999999998 1.2040069999999998 1.2040069999999998 ZT12-15 2.41178 2.41178 2.41178 ZT16-19 1.990675 1.990675 1.990675 ZT20-23 1.7814 1.7814 1.7814