condition mean min max ZT0-3 3.9287425000000002 3.534815 4.3226700000000005 ZT4-7 5.1898800000000005 5.1898800000000005 5.1898800000000005 ZT8-11 3.683695 3.683695 3.683695 ZT12-15 0 0 0 ZT16-19 3.953365 3.953365 3.953365 ZT20-23 4.677065 4.677065 4.677065