condition mean min max ZT0-3 3.526545 1.8515899999999998 4.70429 ZT4-7 2.5088850000000003 2.5088850000000003 2.5088850000000003 ZT8-11 3.536155 3.536155 3.536155 ZT12-15 5.3514675 3.782595 6.9203399999999995 ZT16-19 5.217865 5.217865 5.217865 ZT20-23 6.862285 6.862285 6.862285