ACT Preparation / Unit 21 ACT 2014 worked example, 60 to 90 seconds
Can the Data Show Cause?
The idea
A cause question is answered in three steps. First, decide how the data were collected: by observing existing differences, or by assigning conditions in a controlled experiment. Second, if the data are observational, name a third factor that could produce the association. Third, choose the conclusion the design allows: association for observational data, cause for a well-controlled randomized experiment.
In practice
Worked example: an invented survey finds that gardens with more bees produce more squash. Could the bees cause the larger harvest? The survey only observed; sunnier gardens might attract more bees and also grow more squash. The data support an association. An experiment that netted some plants against bees, chosen at random, could test the cause.
Where people slip
The word causes in an answer choice must be earned by the design. "Is associated with" is the honest claim for observational data.
Your place on the trail
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Builds on
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