condition mean min max ZT0-3 21.410248 21.410248 21.410248 ZT4-7 20.566219 20.566219 20.566219 ZT8-11 19.784065 19.784065 19.784065 ZT12-15 15.012324 15.012324 15.012324 ZT16-19 18.530472 18.530472 18.530472 ZT20-23 20.479623 20.479623 20.479623