condition mean min max ZT0-3 6.39194 6.39194 6.39194 ZT4-7 2.923185 2.923185 2.923185 ZT8-11 4.577515 4.577515 4.577515 ZT12-15 7.826425 7.826425 7.826425 ZT16-19 11.1704 11.1704 11.1704 ZT20-23 8.933295000000001 8.933295000000001 8.933295000000001