11. Hurricane frequencies. The National Hurricane

Chapter 26, Problem 11

(choose chapter or problem)

11. Hurricane frequencies. The National Hurricane Centerprovides data that list the numbers of large (category3, 4, or 5) hurricanes that have struck the United States,by decade since 1851 (http://www.nhc.noaa.gov/Deadliest_Costliest.shtml). The data are on the next page. Recently, theres been some concern that perhaps thenumber of large hurricanes has been increasing. The naturalnull hypothesis would be that the frequency of suchhurricanes has remained constant.a) With 96 large hurricanes observed over the 16 periods,what are the expected value(s) for each cell?b) What kind of chi-square test would be appropriate?c) State the null and alternative hypotheses.d) How many degrees of freedom are there?e) The value of is 12.67. Whats the P-value?f) State your conclusion.g) Look again at the definition of the last decade. Doesthat alter your conclusion at all?