condition mean min max ZT0-3 267.988078 267.988078 267.988078 ZT4-7 315.72848050000005 315.72848050000005 315.72848050000005 ZT8-11 308.731918 308.731918 308.731918 ZT12-15 341.1110735 341.1110735 341.1110735 ZT16-19 272.216136 272.216136 272.216136 ZT20-23 308.9295455 308.9295455 308.9295455