condition mean min max ZT0-3 2.5562966666666664 1.125295 4.05905 ZT4-7 3.9083050000000004 3.9083050000000004 3.9083050000000004 ZT8-11 5.550215 5.550215 5.550215 ZT12-15 3.524115 2.945525 4.102705 ZT16-19 5.846515 5.846515 5.846515 ZT20-23 0.631725 0.631725 0.631725