condition mean min max ZT0-3 2.145485 2.145485 2.145485 ZT4-7 1.774245 1.774245 1.774245 ZT8-11 1.586845 1.586845 1.586845 ZT12-15 1.7179 1.7179 1.7179 ZT16-19 1.835395 1.835395 1.835395 ZT20-23 2.1132150000000003 2.1132150000000003 2.1132150000000003