condition mean min max ZT0-3 6.966446666666666 6.446285 7.630405 ZT4-7 5.771555 5.771555 5.771555 ZT8-11 7.6466 7.6466 7.6466 ZT12-15 12.508075 12.3167 12.699449999999999 ZT16-19 9.714205 9.714205 9.714205 ZT20-23 8.278984999999999 8.278984999999999 8.278984999999999