condition mean min max ZT0-3 14.730717 14.730717 14.730717 ZT4-7 15.345011 15.345011 15.345011 ZT8-11 16.1669355 16.1669355 16.1669355 ZT12-15 13.760368 13.760368 13.760368 ZT16-19 12.2056325 12.2056325 12.2056325 ZT20-23 11.467345 11.467345 11.467345