condition mean min max ZT0-3 6.9589635767499995 3.056201195 10.8617259585 ZT4-7 18.65422958 16.27710661 21.03135255 ZT8-11 30.022528647499996 27.04644161 32.998615685 ZT12-15 29.894054212500002 26.32265074 33.465457685000004 ZT16-19 23.828209355000002 22.73795056 24.918468150000002 ZT20-23 17.9728173425 16.270783695000002 19.67485099