condition mean min max ZT0-3 7.165595 6.604604999999999 7.726585 ZT4-7 8.573935 8.573935 8.573935 ZT8-11 8.854894999999999 8.854894999999999 8.854894999999999 ZT12-15 0 0 0 ZT16-19 12.457650000000001 12.457650000000001 12.457650000000001 ZT20-23 10.92 10.92 10.92