condition mean min max ZT0-3 10.1104725 9.61964 10.601305 ZT4-7 8.114775 8.114775 8.114775 ZT8-11 11.001845 11.001845 11.001845 ZT12-15 0 0 0 ZT16-19 14.257249999999999 14.257249999999999 14.257249999999999 ZT20-23 12.5753 12.5753 12.5753