condition mean min max ZT0-3 7.236655000000001 7.236655000000001 7.236655000000001 ZT4-7 5.087605 5.087605 5.087605 ZT8-11 5.306345 5.306345 5.306345 ZT12-15 7.2157599999999995 7.2157599999999995 7.2157599999999995 ZT16-19 7.672065 7.672065 7.672065 ZT20-23 9.317820000000001 9.317820000000001 9.317820000000001