condition mean min max ZT0-3 2.91066 2.91066 2.91066 ZT4-7 3.20832 3.20832 3.20832 ZT8-11 4.28061 4.28061 4.28061 ZT12-15 3.4616800000000003 3.4616800000000003 3.4616800000000003 ZT16-19 3.8505200000000004 3.8505200000000004 3.8505200000000004 ZT20-23 2.95148 2.95148 2.95148