condition mean min max ZT0-3 15.801943 15.801943 15.801943 ZT4-7 14.9286095 14.9286095 14.9286095 ZT8-11 16.5957285 16.5957285 16.5957285 ZT12-15 13.960763 13.960763 13.960763 ZT16-19 16.297443 16.297443 16.297443 ZT20-23 16.70392 16.70392 16.70392