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Fallibility of Random Assignment
While random assignment is a powerful tool, it does not guarantee that all extraneous variables will be perfectly controlled. Due to chance, experimental groups may still end up differing on certain traits. However, this is rarely a major concern because random assignment is highly effective in large samples, inferential statistics account for this potential random error, and any resulting confounding variables are typically detected when the experiment is replicated.
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Research Methods in Psychology - 4th American Edition @ KPU
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Role of Random Assignment in Ensuring Group Comparability
A researcher wants to test if a new type of energy drink improves performance on a memory test. After recruiting 100 volunteers, which of the following procedures is the most effective way to create an experimental group (receives the energy drink) and a control group (receives a placebo)?
Block Randomization
Fallibility of Random Assignment
Random Assignment vs. Random Sampling
Modified Random Assignment
Software for Randomization
Using a Random Number Generator to Understand Randomization
Example of Simple Random Assignment
What is the primary function of random assignment in an experimental design?
A researcher assigns the first 30 participants who arrive at the lab to the treatment group and the next 30 participants to the control group. This method successfully achieves random assignment because both groups have an equal number of participants.
Match each core requirement or outcome of random assignment with the description that best explains its role in ensuring a fair experiment.
Ensuring Randomness and Statistical Power in Randomized Controlled Trials
In a between-subjects experiment, random assignment is the primary tool for establishing internal validity. Sequence the following steps to represent the logical progression from the initial procedural action to the final scientific conclusion.
A research team is designing an automated system for a study where they will compare three groups: Condition A, Condition B, and Condition C. To construct a protocol that strictly satisfies the definition of random assignment, which logic should the team program into their system?
Strictly speaking, random assignment requires that every participant has an equal probability of being placed in any condition and that each individual's assignment is completely independent of the others.
To effectively control for extraneous variables, researchers must follow a specific procedural logic. Arrange the following steps to correctly sequence the process of random assignment for participants in an experiment.
A researcher evaluates an experimental protocol where participants who arrive at the lab in pairs are always assigned to the same condition to ensure they remain together. Methodologically, this protocol is flawed because it fails to satisfy the strict definition of random assignment, which requires that every individual's placement must be completely _____ of the others.
Match each component or requirement of random assignment with its correct description based on the strict methodological definition.
A researcher evaluates an experimental protocol where participants who arrive together are always placed in the same group. This protocol violates the strict definition of random assignment because each participant's assignment is not _____ of the others.
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Why might experimental groups still differ on certain traits even after researchers use random assignment?
Match each concept related to the fallibility of random assignment with the statement that best describes its role in the research process.
A researcher randomly assigns 20 participants to either a meditation or a control group. Upon reviewing the baseline data, she discovers that the meditation group happens to have a higher average level of 'openness to experience' than the control group. True or False: This initial difference between groups is definitive proof that the random assignment procedure was performed incorrectly.
Random assignment is a powerful but fallible tool because it cannot perfectly control for all extraneous variables in every study. Arrange the components of the scientific 'safety net' in the logical order they function to handle the risk of chance differences, starting from the point where random error is introduced to the point where it is finally detected by the scientific community.
Random assignment provides an absolute guarantee that all extraneous variables will be perfectly controlled in an experiment.
Random assignment is a powerful but 'fallible' tool in experimental research. Which of the following best explains why this fallibility is manageable within the scientific process?
A researcher finds a significant result in a study with a small sample () but worries that random assignment might have 'failed' by creating groups that differed on a hidden variable by chance. To evaluate the validity of the finding, the most definitive tool the scientific community uses to detect such accidental confounding variables is _____.
Match each researcher's action with the corresponding mechanism that addresses the fallibility of random assignment.
A researcher randomly assigns participants to two groups, but due to chance, one group is older on average than the other. To analyze whether the difference in post-test scores is due to the independent variable rather than this random baseline difference, the researcher must rely on _____ to mathematically account for this potential random error.
Evaluate the progression of how a potential failure of random assignment is managed within the scientific method by ordering these steps from the initial assignment to the final verification safeguard.