condition mean min max ZT0-3 10.700505 10.22646 11.17455 ZT4-7 8.73856 8.73856 8.73856 ZT8-11 6.8300149999999995 6.8300149999999995 6.8300149999999995 ZT12-15 0 0 0 ZT16-19 10.30809 10.30809 10.30809 ZT20-23 13.24165 13.24165 13.24165