condition mean min max ZT0-3 25.079921 25.079921 25.079921 ZT4-7 15.926379 15.926379 15.926379 ZT8-11 17.595575500000002 17.595575500000002 17.595575500000002 ZT12-15 15.101744499999999 15.101744499999999 15.101744499999999 ZT16-19 22.1784125 22.1784125 22.1784125 ZT20-23 18.9406425 18.9406425 18.9406425