condition mean min max ZT0-3 2.6135450000000002 2.6135450000000002 2.6135450000000002 ZT4-7 1.642935 1.642935 1.642935 ZT8-11 3.87092 3.87092 3.87092 ZT12-15 2.203565 2.203565 2.203565 ZT16-19 3.920305 3.920305 3.920305 ZT20-23 3.0590200000000003 3.0590200000000003 3.0590200000000003