condition mean min max ZT0-3 22.069883333333333 18.04555 24.338900000000002 ZT4-7 18.0938 18.0938 18.0938 ZT8-11 14.915199999999999 14.915199999999999 14.915199999999999 ZT12-15 28.726325 27.8046 29.648049999999998 ZT16-19 26.884349999999998 26.884349999999998 26.884349999999998 ZT20-23 27.1111 27.1111 27.1111