condition mean min max ZT0-3 5.17056840425 5.0352319565 5.305904852 ZT4-7 3.4166148412500004 3.0711316655 3.7620980170000005 ZT8-11 2.74214397025 2.3763568829999997 3.1079310575 ZT12-15 11.715607080249999 7.4359631805 15.995250979999998 ZT16-19 22.055552685 18.36379968 25.747305689999997 ZT20-23 25.701397739999997 24.013171625 27.389623854999996