With all the discussion about climate change in the past couple of decades, it is no surprise that the occurrence of several intense hurricanes over the past several years has garnered some attention. You may remember that in 2005 the U. S. Gulf coast was hit by hurricanes Emily, Katrina, and Rita. All three were category five on the Saffir-Simpson scale. That is the highest intensity on this five- level scale. The Data set hurricanes contains 59 lines, one for each year from 1950 through 2008. For each year, there are five columns of data containing counts of the number of hurricanes of each category type on the Saffir-Simpson scale (labeled cat1, cat2, cat3, cat4, or cat5). The data were obtained from weather.unisys.com/hurricane/atlantic.
a. Model the total count of time (the covariate) and report whether you find a significant time trend in the count. Of course, check graphically that the model you propose seems reasonable, examine the residuals, and use Wald’s test or a deviance test to make your decision.
b. Repeat the process in Part A, using the count of intense hurricanes per year (category three or higher) as the response.