condition mean min max ZT0-3 21.37625 21.37625 21.37625 ZT4-7 17.5377 17.5377 17.5377 ZT8-11 15.4404 15.4404 15.4404 ZT12-15 17.067349999999998 17.067349999999998 17.067349999999998 ZT16-19 20.473 20.473 20.473 ZT20-23 21.3795 21.3795 21.3795