Situations comparing two proportions are described. In each case , determine whether the situation involves comparing proportions for two groups or comparing two proportions from the same group.
a) Compare the proportion of U.S. adults who have a positive opinion about the media and the proportion of U.S. adults who have a negative opinion about the media.
b) Compare proportion of milk chocolate M&M's that are blue to the proportion of milk chocolate M&M's that are green.
c) Compare the proportion of female students at a university who play a sport to the proportion of male students at a university who play a sport.