An excellent earnings report combined with low interest rates equals an enthusiastic market response.Shares of Carnival (CCL -0.46%) (CUK -0.45%) stock jumped 19% in October, according to data from S&P Global Market Intelligence. It delivered an outstanding earnings report going into the month, and it's also benefiting from improved investor sentiment based on lower interest rates.Travelers love cruisesCarnival's revenue touched zero during the worst part of the pandemic, but that's not because it fell out ...