condition mean min max ZT0-3 2.553885 2.31939 2.78838 ZT4-7 3.1558900000000003 3.1558900000000003 3.1558900000000003 ZT8-11 2.01817 2.01817 2.01817 ZT12-15 0 0 0 ZT16-19 2.52574 2.52574 2.52574 ZT20-23 3.5106900000000003 3.5106900000000003 3.5106900000000003