condition mean min max ZT0-3 20.884886 20.884886 20.884886 ZT4-7 20.2691635 20.2691635 20.2691635 ZT8-11 22.284005 22.284005 22.284005 ZT12-15 19.82844 19.82844 19.82844 ZT16-19 22.8963705 22.8963705 22.8963705 ZT20-23 40.8530975 40.8530975 40.8530975