condition mean min max ZT0-3 7.814396 7.814396 7.814396 ZT4-7 7.91183 7.91183 7.91183 ZT8-11 7.622593 7.622593 7.622593 ZT12-15 7.9801585 7.9801585 7.9801585 ZT16-19 7.520957 7.520957 7.520957 ZT20-23 8.1042185 8.1042185 8.1042185