What term describes the deviation of individual scores within each group from the group mean that is not due to a confounding variable?

What term describes the deviation of individual scores within each group from the group mean that is not due to a confounding variable?

• A. Error variance (unsystematic)
• B. Error variance (systematic)
• C. Internal validity
• D. Quasi-experiment

Answer: (A)

The key idea is that some variability in scores within a group is just random noise not linked to any manipulated factor or confounding variable. The deviations of individuals from their group mean that aren’t explained by the treatment or by confounds represent unsystematic error variance—random measurement error and unexplained individual differences. This is the portion of variance you cannot attribute to systematic factors. Systematic error would come from a confounding influence that biases scores in a consistent way, internal validity concerns how well a study supports causal conclusions, and a quasi-experiment refers to a design without random assignment—none of these describe this random, non-confounded within-group variation.

The key idea is that some variability in scores within a group is just random noise not linked to any manipulated factor or confounding variable. The deviations of individuals from their group mean that aren’t explained by the treatment or by confounds represent unsystematic error variance—random measurement error and unexplained individual differences. This is the portion of variance you cannot attribute to systematic factors. Systematic error would come from a confounding influence that biases scores in a consistent way, internal validity concerns how well a study supports causal conclusions, and a quasi-experiment refers to a design without random assignment—none of these describe this random, non-confounded within-group variation.