condition mean min max ZT0-3 4.204181666666667 3.092465 4.961325 ZT4-7 2.57486 2.57486 2.57486 ZT8-11 4.88381 4.88381 4.88381 ZT12-15 7.377305 7.006489999999999 7.74812 ZT16-19 8.907775 8.907775 8.907775 ZT20-23 7.608790000000001 7.608790000000001 7.608790000000001