condition mean min max ZT0-3 18.92314170375 14.2783394075 23.567944 ZT4-7 7.873680554250001 7.32747931 8.4198817985 ZT8-11 10.17654560425 8.3931493135 11.959941895 ZT12-15 8.757134079499998 8.304698453499999 9.2095697055 ZT16-19 6.81027929375 6.5572133075 7.06334528 ZT20-23 8.0711055755 7.4909216595 8.651289491500002