condition mean min max ZT0-3 2.983146666666667 2.036055 3.4931850000000004 ZT4-7 1.8068650000000002 1.8068650000000002 1.8068650000000002 ZT8-11 1.8617650000000001 1.8617650000000001 1.8617650000000001 ZT12-15 3.6851625 3.5305400000000002 3.839785 ZT16-19 3.59944 3.59944 3.59944 ZT20-23 4.2318750000000005 4.2318750000000005 4.2318750000000005