condition mean min max ZT0-3 8.364412 8.364412 8.364412 ZT4-7 8.924619 8.924619 8.924619 ZT8-11 7.761851500000001 7.761851500000001 7.761851500000001 ZT12-15 7.635011 7.635011 7.635011 ZT16-19 8.041125 8.041125 8.041125 ZT20-23 8.4225675 8.4225675 8.4225675