condition mean min max ZT0-3 17.249576 17.249576 17.249576 ZT4-7 18.036844 18.036844 18.036844 ZT8-11 17.182582 17.182582 17.182582 ZT12-15 17.9948345 17.9948345 17.9948345 ZT16-19 22.111296000000003 22.111296000000003 22.111296000000003 ZT20-23 13.8899305 13.8899305 13.8899305