Aschool wants to build a new athletic building for sports practices, but must receive enough votes at the next election for funding for the new building. they survey the parents at a football game to find out if they will vote for funding of the new athletic building in the next election. is this sample likely to be biased or unbiased?

This survey will definitely suffer from bias because the parents at the football game are not representative of the whole voting population.
If the goal is to find out the proportion of adults who would vote for the funding (to see if the funding would be approved), then there is bias for at least two different reasons: one, because the adults being surveyed are parents of students, they are probably more likely to support funding since they have a kid at the school. And two, since we are taking samples at a sporting event, there is an even higher likelihood of support of the funding because the people attending the game value athletic activities. It's likely that the proportion of adults at the game who would vote in favor of the funds is higher than the proportion of the whole population that is in favor.

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