Understanding Experiments and Observational Studies

In an experiment, what does the researcher do?

• Changes a variable or imposes a treatment.

• Classifies subjects into groups without changing behavior.

• Asks questions without changing variables.

• Only observes without interference.

What is the main difference between a population and a sample?

• A population is a subset of a sample.

• A population is the entire group, while a sample is a part of that group.

• A sample includes the entire population.

• A sample is always larger than a population.

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CCSS.HSS.IC.A.1

Which of the following best describes an observational study?

• Observing or asking questions without changing variables.

• Changing variables to observe effects.

• Imposing treatments on subjects.

• Conducting experiments in a lab.

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What is a sample survey?

• A survey that changes variables.

• An experiment conducted on a sample.

• A survey given to a sample of people.

• A survey given to the entire population.

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Which of the following is an example of an experiment?

• Surveying people about their bedtime habits.

• Classifying social media users into groups.

• Observing people's social media habits without interference.

• Telling one group to drink tea and another not to, then comparing results.

What is the key characteristic of an observational study?

• Imposing treatments on subjects.

• Changing variables to observe effects.

• Conducting experiments in a controlled environment.

• Gathering data without changing behavior.

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CCSS.HSS.IC.B.3

In the example where adults were asked about their bedtime habits, what type of study was conducted?

• Randomized experiment

• Controlled trial

• Observational study

• Experiment

What was the purpose of dividing adults into two groups and instructing one to drink tea and the other not to?

• To classify subjects into groups.

• To conduct an experiment.

• To conduct a sample survey.

• To conduct an observational study.

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CCSS.HSS.IC.B.3

When researchers classify social media users into light, moderate, or heavy users without changing their behavior, what type of study is this?

• Experiment

• Observational study

• Randomized experiment

• Controlled trial

What is the main difference between an observational study and an experiment?

• Observational studies change variables, experiments do not.

• Both change variables but in different ways.

• Neither change variables.

• Experiments change variables, observational studies do not.