condition mean min max ZT0-3 3.1492975000000003 3.1100000000000003 3.188595 ZT4-7 2.197755 2.197755 2.197755 ZT8-11 2.757465 2.757465 2.757465 ZT12-15 0 0 0 ZT16-19 4.192985 4.192985 4.192985 ZT20-23 5.160159999999999 5.160159999999999 5.160159999999999