condition mean min max ZT0-3 6.80827 1.771955 12.05595 ZT4-7 5.328335 5.328335 5.328335 ZT8-11 36.45455 36.45455 36.45455 ZT12-15 17.479075 16.1919 18.76625 ZT16-19 13.00765 13.00765 13.00765 ZT20-23 12.612715 12.612715 12.612715