condition mean min max ZT0-3 1.21568537925 0.76755914 1.6638116185 ZT4-7 2.8562579987500003 2.5268766815 3.185639316 ZT8-11 3.2382533002500002 3.1328229590000003 3.3436836415 ZT12-15 6.3484551005 5.0882550795000006 7.608655121499999 ZT16-19 9.1624410545 7.845949528999999 10.47893258 ZT20-23 13.86170096 12.752367025 14.971034894999999