condition mean min max ZT0-3 4.327505 4.327505 4.327505 ZT4-7 5.1603200000000005 5.1603200000000005 5.1603200000000005 ZT8-11 6.151339999999999 6.151339999999999 6.151339999999999 ZT12-15 7.28721 7.28721 7.28721 ZT16-19 4.99751 4.99751 4.99751 ZT20-23 2.96948 2.96948 2.96948