Every year, there are more than 300,000 robberies in the

Every year, there are more than 300,000 robberies in the United States. A researcher took a random sample of robberies in 2000, 2005, and 2010, and recorded the weapon used (1 = Firearm, 2 = Knife or other cutting instrument, 3 = other, 4 = No weapon). Is there sufficient evidence to infer that the frequency of the use of weapons in robberies differed over the three years?