condition mean min max ZT0-3 36.623875 0.0 108.6842 ZT4-7 62.6695 62.6695 62.6695 ZT8-11 7.68849 7.68849 7.68849 ZT12-15 6.78468 4.925895 8.643465 ZT16-19 1.959505 1.959505 1.959505 ZT20-23 0.426442 0.426442 0.426442