condition mean min max ZT0-3 0.827435 0.604437 1.1861350000000002 ZT4-7 1.506405 1.506405 1.506405 ZT8-11 1.9735550000000002 1.9735550000000002 1.9735550000000002 ZT12-15 4.269865 4.0620650000000005 4.477665 ZT16-19 2.690335 2.690335 2.690335 ZT20-23 1.413485 1.413485 1.413485