condition mean min max ZT0-3 4.0484725 3.76361 4.333335 ZT4-7 3.9867850000000002 3.9867850000000002 3.9867850000000002 ZT8-11 3.3749599999999997 3.3749599999999997 3.3749599999999997 ZT12-15 0 0 0 ZT16-19 5.0384899999999995 5.0384899999999995 5.0384899999999995 ZT20-23 3.6340950000000003 3.6340950000000003 3.6340950000000003