condition mean min max ZT0-3 7.3308225 6.704924999999999 7.95672 ZT4-7 12.2742 12.2742 12.2742 ZT8-11 4.57424 4.57424 4.57424 ZT12-15 0 0 0 ZT16-19 6.4976 6.4976 6.4976 ZT20-23 7.923325 7.923325 7.923325