condition mean min max ZT0-3 0.2283535 0.2283535 0.2283535 ZT4-7 0.5311965 0.5311965 0.5311965 ZT8-11 0.720242 0.720242 0.720242 ZT12-15 0.8739250000000001 0.8739250000000001 0.8739250000000001 ZT16-19 1.2353649999999998 1.2353649999999998 1.2353649999999998 ZT20-23 0.969241 0.969241 0.969241