condition mean min max ZT0-3 18.99631 18.99631 18.99631 ZT4-7 21.7593935 21.7593935 21.7593935 ZT8-11 19.036611 19.036611 19.036611 ZT12-15 18.636675 18.636675 18.636675 ZT16-19 18.65336 18.65336 18.65336 ZT20-23 21.635066000000002 21.635066000000002 21.635066000000002