condition mean min max ZT0-3 18.4407 17.725 19.1564 ZT4-7 20.258200000000002 20.258200000000002 20.258200000000002 ZT8-11 19.6914 19.6914 19.6914 ZT12-15 0 0 0 ZT16-19 21.558500000000002 21.558500000000002 21.558500000000002 ZT20-23 24.031950000000002 24.031950000000002 24.031950000000002