condition mean min max ZT0-3 2.6397603702500003 2.4830856470000002 2.7964350935 ZT4-7 1.6101618963333335 1.5351926063333334 1.6851311863333334 ZT8-11 1.3679873565 1.1186450639999999 1.617329649 ZT12-15 1.1606074418333332 1.0557077363333334 1.2655071473333332 ZT16-19 0.6615289635 0.620621471 0.702436456 ZT20-23 0.5082882995 0.357304583 0.6592720160000001