condition mean min max ZT0-3 12.838750000000001 12.838750000000001 12.838750000000001 ZT4-7 8.210625 8.210625 8.210625 ZT8-11 9.369873333333333 9.369873333333333 9.369873333333333 ZT12-15 9.927505 9.927505 9.927505 ZT16-19 10.852935 10.852935 10.852935 ZT20-23 9.08533 9.08533 9.08533