condition mean min max ZT0-3 4.925445 4.925445 4.925445 ZT4-7 2.644875 2.644875 2.644875 ZT8-11 3.068635 3.068635 3.068635 ZT12-15 3.43707 3.43707 3.43707 ZT16-19 8.3786 8.3786 8.3786 ZT20-23 5.625325 5.625325 5.625325