condition mean min max ZT0-3 10.6228106505 6.909618859 14.336002442 ZT4-7 16.7857152 15.696682465 17.874747935 ZT8-11 17.7086916175 16.01768736 19.399695875 ZT12-15 18.77572919 15.657559385 21.893898995 ZT16-19 19.522660665 19.078639324999997 19.966682005000003 ZT20-23 21.57563049 21.30011719 21.851143790000002