Random assignment is important in grouping participants in a research study because ________.

• A. it guarantees that every participant receives the experimental treatment
• B. it allows researchers to generalize findings to the entire population without further analysis
• C. it eliminates the need for a control group in the study
• D. it helps ensure that differences between groups are due to the independent variable and not preexisting differences among participants

Answer: (D)

Verified step by step guidance

1. Understand the purpose of random assignment in research studies: it is a method used to place participants into different groups (e.g., experimental and control groups) in a way that each participant has an equal chance of being assigned to any group.
2. Recognize that random assignment helps control for confounding variables by distributing participant characteristics evenly across groups, which reduces the likelihood that preexisting differences will influence the results.
3. Identify that this process increases the internal validity of the study by ensuring that observed differences between groups can be attributed to the independent variable rather than other factors.
4. Note that random assignment does not guarantee every participant receives the experimental treatment; rather, it ensures fair and unbiased group allocation.
5. Conclude that the main importance of random assignment is to help ensure that differences between groups are due to the independent variable and not preexisting differences among participants.