condition mean min max ZT0-3 11.375505555 10.5989391 12.15207201 ZT4-7 6.721710512 6.056713274 7.38670775 ZT8-11 4.240025365 3.9547805895000003 4.5252701405 ZT12-15 3.455231875 3.2894781689999997 3.6209855810000002 ZT16-19 2.86399508425 2.7570421019999998 2.9709480665 ZT20-23 5.3873976822500005 4.9506130395 5.824182325000001