Atown’s athletic league contains 18 baseball teams. the board members of the league want to survey adults attending games to determine if they believe the athletes are showing good sportsmanship. the board members attended one game and surveyed an equal number of adults supporting each of the two teams. which best explains the validity of the results? a).invalid because of biased sampling b).invalid because the sampled adults are not part of the population c).valid because an equal number of adults supporting both teams were surveyed d).valid because adults are the target population

Right off the bat (haha), we can eliminate B as an answer choice because adults are clearly part of the population; in fact, it says in the background information that their entire population is made of adults.  A population, in this context, is the group being researched.

D isn't the correct answer; the fact that adults are the target population doesn't validify anything.

C doesn't entirely prove its point because there are other factors that go into the game being biased.  In fact, I would say that this study is biased because the board members only attended 1 game when there are 18 teams.  Their data will only pertain to fans of the 2 teams playing each other, and not represent the population as a whole.

A would be my answer for reasons stated above.