condition mean min max ZT0-3 19.981075 19.195 20.76715 ZT4-7 15.452350000000001 15.452350000000001 15.452350000000001 ZT8-11 15.37635 15.37635 15.37635 ZT12-15 0 0 0 ZT16-19 18.3559 18.3559 18.3559 ZT20-23 16.480649999999997 16.480649999999997 16.480649999999997