condition mean min max ZT0-3 3.3755100000000002 3.3755100000000002 3.3755100000000002 ZT4-7 2.647045 2.647045 2.647045 ZT8-11 2.63395 2.63395 2.63395 ZT12-15 2.369335 2.369335 2.369335 ZT16-19 3.166225 3.166225 3.166225 ZT20-23 2.89617 2.89617 2.89617