Research Variables. Compare independent variables dependent variables and extraneous variables. Describe two ways that researchers attempt to control extraneous variables. Provide an example of how this is applied using a peer-reviewed, primary research article.
Independent Variables: These are factors that researchers manipulate or control in an experiment. They are the variables that researchers believe have a causal effect on the dependent variable. For instance, in a study investigating the effect of different doses of a drug on blood pressure, the independent variable would be the dosage of the drug…..Research Variables…..
Dependent Variables: These variables are the outcomes or effects that researchers measure. They depend on the changes in the independent variable. In the same drug dosage study, the dependent variable would be the blood pressure readings taken after administering each dosage.
Extraneous Variables: These are variables that are not of primary interest in the study but could affect the dependent variable. They can potentially confound the results by introducing unintended influence. Factors like environmental conditions, participant characteristics, or measurement errors can be extraneous variables…..Research Variables…..
Ways to Control Extraneous Variables:
- Randomization: Researchers use random assignment to allocate participants into different groups or conditions. This minimizes the impact of extraneous variables by distributing them evenly across groups, reducing the likelihood that they systematically influence the results. For example, in a drug trial, random assignment ensures that participant characteristics (like age, gender, or health status) are equally distributed among the groups receiving different dosages.
- Experimental Design: Careful experimental design can help control extraneous variables. For instance, using control groups that receive a placebo or standard treatment helps isolate the effect of the independent variable. This allows researchers to compare the outcomes with and without the manipulation of the independent variable.
Example from a Research Article:
In a peer-reviewed article titled “Effects of Exercise on Cognitive Function in Older Adults: A Meta-Analysis,” researchers conducted a meta-analysis to examine the impact of exercise on cognitive function in older adults.
- Independent Variable: Exercise (the type, duration, and intensity)
- Dependent Variable: Cognitive function (measured by various cognitive tests)
- Extraneous Variables: Age, gender, baseline cognitive status, comorbidities
Control of Extraneous Variables: The researchers controlled extraneous variables by:
- Inclusion Criteria: They selected studies with similar participant demographics (age range, health status) to minimize variation in baseline characteristics.
- Subgroup Analysis: They performed subgroup analyses based on exercise type and duration to evaluate the impact on cognitive function across different variables while controlling for potential confounders.
By employing strict inclusion criteria and conducting subgroup analyses, the researchers attempted to minimize the impact of extraneous variables and isolate the effect of exercise on cognitive function in older adults.
This approach illustrates how researchers in a peer-reviewed study used careful selection criteria and analyses to control for extraneous variables and enhance the internal validity of their findings.