Answer:
The full question is
<em>What are the differences among an experiment, a study, and a survey?
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<em>1. In an observational study, randomization of subjects ______
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<em>A. occurs
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<em>B. does not occur
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We understand randomization as a random process of assigning experimental subjects to treatment groups. Through this process, we have more control about variables which are not related to the experiment.
In an observational study, the researcher doesn't change anything, he or she studies the events as they are, without using any randomization process.
Therefore, the right answer here is B.<em>
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<em>2. A survey _______
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<em>A. poses no interference on subjects
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<em>B. makes inferences about a population
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</em>A survey poses no interference on subjects, actually if it does, then that survey is not reliable. An important charactersitic of a survey is that it must be objective, that way it will be reliable enough to use it in the research.
Therefore, the right answer is A.
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<em>3. In an experiment, ___________ to discern differences in a response variable.
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<em>A. treatment is imposed
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<em>B. inferences are made
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<em>C. randomization does not occur</em>
Experiments are characterized by having certain "stimulus" at least in one group of subjects, that way researches compare data sets to prove their hypothesis.
Therefore, the right answer here is A.
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