condition mean min max ZT0-3 21.593275 20.2799 22.90665 ZT4-7 19.404899999999998 19.404899999999998 19.404899999999998 ZT8-11 25.30755 25.30755 25.30755 ZT12-15 0 0 0 ZT16-19 29.50325 29.50325 29.50325 ZT20-23 22.518900000000002 22.518900000000002 22.518900000000002