Back to Distinguish surveys, experiments, and observational studies — Problem 1 · Task Set 14

Exercises: Distinguish Surveys, Experiments, and Observational Studies

Work through each section in order. For classification problems, decide whether a study is a sample survey, an observational study, or a randomized experiment, and use two separate questions: "Was there random SELECTION?" (which governs whether results generalize to a population) and "Was there random ASSIGNMENT?" (which governs whether a difference can be read as causation). For explanation problems, write in complete sentences.

Grade 10·21 problems·~35 min·Common Core Math - HS Statistics and Probability·group·hss-ic-b-3

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Fluency Practice

Classify each study and identify the role of randomization.

A polling company randomly selects 2,000 adults and asks each whether they exercise daily and how they rate their health. Even with a huge sample, which conclusion can this survey support?

It can estimate and generalize a population characteristic and show association, but it cannot establish that exercise causes better health.

It can prove that exercise causes better health, because the sample is large.

It can prove causation only if the sample is at least 5,000 people.

It can conclude nothing at all, because surveys are unreliable.