condition mean min max ZT0-3 14.607075 13.456 15.75815 ZT4-7 6.6515450000000005 6.6515450000000005 6.6515450000000005 ZT8-11 2.023225 2.023225 2.023225 ZT12-15 0 0 0 ZT16-19 5.566265 5.566265 5.566265 ZT20-23 12.2043 12.2043 12.2043