condition mean min max ZT0-3 19.12534 19.12534 19.12534 ZT4-7 19.12534 19.12534 19.12534 ZT8-11 17.5265425 17.5265425 17.5265425 ZT12-15 15.776905000000001 15.776905000000001 15.776905000000001 ZT16-19 20.090751500000003 20.090751500000003 20.090751500000003 ZT20-23 18.503807000000002 18.503807000000002 18.503807000000002