condition mean min max ZT0-3 3.553715 3.553715 3.553715 ZT4-7 3.106555 3.106555 3.106555 ZT8-11 2.62478 2.62478 2.62478 ZT12-15 3.598345 3.598345 3.598345 ZT16-19 4.813015 4.813015 4.813015 ZT20-23 3.3954 3.3954 3.3954