condition mean min max ZT0-3 4.911196666666666 3.76082 6.02488 ZT4-7 4.64936 4.64936 4.64936 ZT8-11 8.404589999999999 8.404589999999999 8.404589999999999 ZT12-15 12.981275 9.8001 16.16245 ZT16-19 10.157725 10.157725 10.157725 ZT20-23 6.54895 6.54895 6.54895