condition mean min max ZT0-3 22.892819 22.892819 22.892819 ZT4-7 26.3732115 26.3732115 26.3732115 ZT8-11 21.335724 21.335724 21.335724 ZT12-15 26.002235499999998 26.002235499999998 26.002235499999998 ZT16-19 20.1183805 20.1183805 20.1183805 ZT20-23 20.256182000000003 20.256182000000003 20.256182000000003