condition mean min max ZT0-3 2.1037600000000003 2.1037600000000003 2.1037600000000003 ZT4-7 1.355915 1.355915 1.355915 ZT8-11 2.255375 2.255375 2.255375 ZT12-15 2.86886 2.86886 2.86886 ZT16-19 3.4798999999999998 3.4798999999999998 3.4798999999999998 ZT20-23 2.522565 2.522565 2.522565