MA19.A2.29 | ALEX

Mathematics (2019) Grade(s): 09-12 - Algebra II with Statistics

MA19.A2.29

Explain the consequences, due to uncontrolled variables, of non-randomized assignment of subjects to groups in experiments.

COS Examples
Example: Students are studying whether or not listening to music while completing mathematics homework improves their quiz scores. Rather than assigning students to either listen to music or not at random, they simply observe what the students do on their own and find that the music-listening group has a higher mean quiz score. Can they conclude that listening to music while studying is likely to raise the quiz scores of students who do not already listen to music? What other factors may have been responsible for the observed difference in mean quiz scores?

Unpacked Content

Knowledge

Students know:

Differences between random and non-random assignment.
The definition of independent and dependent variables.

Skills

Students are able to:

Conclude whether a causal relationship exists in an experiment based on the type of assignment of subjects in the experiment.
Identify uncontrolled variable that may be responsible for observed difference when non-randomized assignment is used in an experiment.

Understanding

Students understand that:

Uncontrolled variables are characteristic factors that are not regulated or measured by the investigator during an experiment or study, so that they are not the same for all participants in the research.
Randomized selection of subjects to groups in experiments is the only type of study able to establish causation.

Vocabulary

Uncontrolled variables
Non-randomized

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