condition mean min max ZT0-3 34.142395 34.142395 34.142395 ZT4-7 12.920561 12.920561 12.920561 ZT8-11 13.6990135 13.6990135 13.6990135 ZT12-15 15.231584 15.231584 15.231584 ZT16-19 12.631450000000001 12.631450000000001 12.631450000000001 ZT20-23 15.2123875 15.2123875 15.2123875