A research organization keeps track of what citizens think is the most important problem facing the country today. They randomly sampled a number of people in 2003 and again in 2009 using a different random sample of people in 2009 than in 2003 and asked them to choose the most important problem facing the country today from the following choices, war, economy, health care, or other. Which of the following is the correct test to use to determine if the distribution of "problem facing this countrytoday" is different between the two different years? A.

Use a chi-square test of homogeneity.

B.

Use a paired t-test.

C.

Use a two-sample z-test for proportions.

D.

Use a chi-square goodness-of-fit test.