condition mean min max ZT0-3 18.08738333333333 12.34815 23.6035 ZT4-7 49.697599999999994 49.697599999999994 49.697599999999994 ZT8-11 61.0213 61.0213 61.0213 ZT12-15 21.942300000000003 21.76425 22.120350000000002 ZT16-19 25.0151 25.0151 25.0151 ZT20-23 15.2086 15.2086 15.2086