condition mean min max ZT0-3 12.16475 12.16475 12.16475 ZT4-7 9.4926 9.4926 9.4926 ZT8-11 6.91976 6.91976 6.91976 ZT12-15 10.51635 10.51635 10.51635 ZT16-19 11.22935 11.22935 11.22935 ZT20-23 13.9805 13.9805 13.9805