condition mean min max ZT0-3 7.9407499999999995 7.9407499999999995 7.9407499999999995 ZT4-7 7.81557 7.81557 7.81557 ZT8-11 7.79016 7.79016 7.79016 ZT12-15 7.79669 7.79669 7.79669 ZT16-19 7.9766 7.9766 7.9766 ZT20-23 7.9550600000000005 7.9550600000000005 7.9550600000000005