condition mean min max ZT0-3 1.5622299585 0.596914296 2.527545621 ZT4-7 4.31523182625 3.665980819 4.9644828335 ZT8-11 5.61927784175 5.045841933 6.1927137505 ZT12-15 9.674555302 7.3240731839999995 12.02503742 ZT16-19 11.3373938475 11.12782642 11.546961275000001 ZT20-23 11.878612281999999 11.469822714 12.287401849999998