condition mean min max ZT0-3 12.5419725 11.95205 13.131895 ZT4-7 25.18395 25.18395 25.18395 ZT8-11 21.189500000000002 21.189500000000002 21.189500000000002 ZT12-15 0 0 0 ZT16-19 12.3015 12.3015 12.3015 ZT20-23 14.066849999999999 14.066849999999999 14.066849999999999