condition mean min max ZT0-3 2.2521940899999997 1.025520724 3.4788674559999997 ZT4-7 1.8854805396666667 1.0547455986666667 2.7162154806666665 ZT8-11 1.9207817819999997 1.605037831 2.2365257329999997 ZT12-15 2.8389944235 2.668780459 3.0092083880000002 ZT16-19 4.314707474 3.789782932 4.839632016 ZT20-23 3.564806240166667 3.3353465703333334 3.79426591