condition mean min max ZT0-3 424.402341 424.402341 424.402341 ZT4-7 545.36428 545.36428 545.36428 ZT8-11 557.0143875 557.0143875 557.0143875 ZT12-15 620.9981445000001 620.9981445000001 620.9981445000001 ZT16-19 650.8616099999999 650.8616099999999 650.8616099999999 ZT20-23 665.259687 665.259687 665.259687