condition mean min max ZT0-3 12.791553 12.791553 12.791553 ZT4-7 12.0600395 12.0600395 12.0600395 ZT8-11 12.565469 12.565469 12.565469 ZT12-15 13.616398499999999 13.616398499999999 13.616398499999999 ZT16-19 13.541765 13.541765 13.541765 ZT20-23 13.4194085 13.4194085 13.4194085