condition mean min max ZT0-3 5.515445 2.4722549999999996 8.816334999999999 ZT4-7 3.32188 3.32188 3.32188 ZT8-11 3.796195 3.796195 3.796195 ZT12-15 1.63516275 1.4845855000000001 1.78574 ZT16-19 4.59584 4.59584 4.59584 ZT20-23 7.392875 7.392875 7.392875