Using sampling concepts, it is found that the sampled is biased because only parents who attend the school's musical show are surveyed, hence they are not very likely to support the decrease, and the population proportion should be greater than the one found in the show.
Samples may be classified as:
A sample has to take into account all aspects of the population, otherwise it is biased. In this problem, either people support the decrease, or they do not. Only people that went to the show were surveyed, that is, people who are unlikely to support the decrease, which generates bias, as the population proportion should be greater than the one found in the show.
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