condition mean min max ZT0-3 6.61984 6.61984 6.61984 ZT4-7 3.67669 3.67669 3.67669 ZT8-11 5.03603 5.03603 5.03603 ZT12-15 4.846640000000001 4.846640000000001 4.846640000000001 ZT16-19 7.718135 7.718135 7.718135 ZT20-23 6.988065 6.988065 6.988065