condition mean min max ZT0-3 13.435675 13.435675 13.435675 ZT4-7 13.4076485 13.4076485 13.4076485 ZT8-11 13.330915000000001 13.330915000000001 13.330915000000001 ZT12-15 12.994749 12.994749 12.994749 ZT16-19 12.5923325 12.5923325 12.5923325 ZT20-23 13.660921 13.660921 13.660921