condition mean min max ZT0-3 3.4175325 2.25558 4.579485 ZT4-7 8.6099 8.6099 8.6099 ZT8-11 6.41811 6.41811 6.41811 ZT12-15 0 0 0 ZT16-19 1.6529885 1.6529885 1.6529885 ZT20-23 8.301045 8.301045 8.301045