condition mean min max ZT0-3 2.7264221666666666 1.2250415000000001 3.724685 ZT4-7 1.5581369999999999 1.5581369999999999 1.5581369999999999 ZT8-11 1.0614405 1.0614405 1.0614405 ZT12-15 1.69792225 1.081988 2.3138565 ZT16-19 2.672145 2.672145 2.672145 ZT20-23 3.58744 3.58744 3.58744