condition mean min max ZT0-3 3.8603899999999998 3.8603899999999998 3.8603899999999998 ZT4-7 2.306495 2.306495 2.306495 ZT8-11 3.8993700000000002 3.8993700000000002 3.8993700000000002 ZT12-15 5.6789950000000005 5.6789950000000005 5.6789950000000005 ZT16-19 6.17071 6.17071 6.17071 ZT20-23 4.046845 4.046845 4.046845