condition mean min max ZT0-3 26.59585 19.57145 31.52635 ZT4-7 19.3596 19.3596 19.3596 ZT8-11 20.23005 20.23005 20.23005 ZT12-15 27.106625 21.1683 33.04495 ZT16-19 35.295 35.295 35.295 ZT20-23 35.632000000000005 35.632000000000005 35.632000000000005