condition mean min max ZT0-3 6.652215 4.499505 7.99175 ZT4-7 4.102845 4.102845 4.102845 ZT8-11 3.1012250000000003 3.1012250000000003 3.1012250000000003 ZT12-15 4.485545 4.15559 4.8155 ZT16-19 4.53875 4.53875 4.53875 ZT20-23 7.3258600000000005 7.3258600000000005 7.3258600000000005