condition mean min max ZT0-3 3.395495 3.239515 3.551475 ZT4-7 2.1731800000000003 2.1731800000000003 2.1731800000000003 ZT8-11 1.860795 1.860795 1.860795 ZT12-15 0 0 0 ZT16-19 2.47783 2.47783 2.47783 ZT20-23 2.372 2.372 2.372