condition mean min max ZT0-3 2.863045 2.863045 2.863045 ZT4-7 1.9042400000000002 1.9042400000000002 1.9042400000000002 ZT8-11 2.011205 2.011205 2.011205 ZT12-15 2.79619 2.79619 2.79619 ZT16-19 3.0289 3.0289 3.0289 ZT20-23 2.604445 2.604445 2.604445