condition mean min max ZT0-3 30.900000000000002 30.900000000000002 30.900000000000002 ZT4-7 2.8 2.8 2.8 ZT8-11 20.6 20.6 20.6 ZT12-15 28.7 28.7 28.7 ZT16-19 16.8 16.8 16.8 ZT20-23 25.799999999999997 25.799999999999997 25.799999999999997