condition mean min max ZT0-3 12.120349 12.120349 12.120349 ZT4-7 13.019895 13.019895 13.019895 ZT8-11 14.062638 14.062638 14.062638 ZT12-15 12.854743 12.854743 12.854743 ZT16-19 15.223237000000001 15.223237000000001 15.223237000000001 ZT20-23 14.5702575 14.5702575 14.5702575