condition mean min max ZT0-3 6.588765 6.588765 6.588765 ZT4-7 5.39072 5.39072 5.39072 ZT8-11 14.97805 14.97805 14.97805 ZT12-15 23.124000000000002 23.124000000000002 23.124000000000002 ZT16-19 12.450949999999999 12.450949999999999 12.450949999999999 ZT20-23 8.26113 8.26113 8.26113