Big Ideas Math: Modeling Real Life, Grade 7
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Big Ideas Math: Modeling Real Life, Grade 7 View details
Practice Test
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Exercise 1 Page 354

Is this sample representative?

Biased, see solution.

We survey 5 students who are standing in the lunch line to estimate the number of students in our school who prefer to bring a lunch from home rather than buy one at school. We want to decide if this sample is biased or unbiased. To do so, let's remember what we know about these types of samples.
Definition
Unbiased Sample An unbiased sample is representative, which means that its results are proportional to the results of a population. We can use unbiased samples to make conclusions about a population.
Biased Sample A biased sample overrepresents or underrepresents a certain part of the population, which makes it not representative. We should not use biased samples to make conclusions about a population.

The sample is biased because students standing in the lunch line are likely not to prefer bringing lunch from home. They surely do not want to pass on Sloppy Joe's!