In December 2001, the Department of Veterans Affairs announced that it would begin paying benefits to soldiers suffering from Lou Gehrig's disease who had served in the Gulf War (The New York Times, December 11, 2001). This decision was based on an analysis in which the Lou Gehrig's disease incidence rate (the proportion developing the disease) for all of the approximately 700,000 soldiers sent to the Gulf between August 1990 and July 1991 was compared to the incidence rate for all of the approximately 1.8 million other soldiers who were not in the Gulf during this time period. Based on these data, explain why it is not appropriate to perform a formal inference procedure (such as the two-sample z test) and yet it is still reasonable to conclude that the incidence rate is greater for Gulf War veterans than for those who did not serve in the Gulf.