condition mean min max ZT0-3 8.666820577 8.206000638999999 9.127640515 ZT4-7 3.8767440639999995 3.3932387645 4.3602493634999995 ZT8-11 2.9819678685 2.3572126735 3.6067230635000005 ZT12-15 3.9911275895000005 3.9698403975 4.0124147815 ZT16-19 7.647367191500001 6.8261337765 8.4686006065 ZT20-23 9.586941428750002 9.014247352 10.159635505500002