condition mean min max ZT0-3 2.9689133333333335 2.37427 3.62294 ZT4-7 1.4490345 1.4490345 1.4490345 ZT8-11 9.93459 9.93459 9.93459 ZT12-15 7.8955625 6.80861 8.982515 ZT16-19 4.387779999999999 4.387779999999999 4.387779999999999 ZT20-23 2.84163 2.84163 2.84163