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What is the purpose of using a double-blind experiment in research?
What is the purpose of using a double-blind experiment in research?
How does a larger sample size affect statistical testing?
How does a larger sample size affect statistical testing?
What characterizes a true experimental design?
What characterizes a true experimental design?
What is the role of a placebo group in randomized experiments?
What is the role of a placebo group in randomized experiments?
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What does sampling error refer to in research studies?
What does sampling error refer to in research studies?
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What is the main purpose of randomization in a Completely Randomized Design?
What is the main purpose of randomization in a Completely Randomized Design?
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Which term describes the smallest unit of observation in an experiment?
Which term describes the smallest unit of observation in an experiment?
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What is the role of a control group in an experiment?
What is the role of a control group in an experiment?
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What is a Randomized Control Trial (RCT) primarily designed to do?
What is a Randomized Control Trial (RCT) primarily designed to do?
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What do random effects in a model signify?
What do random effects in a model signify?
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In a Completely Randomized Design, what does the term 'treatment' refer to?
In a Completely Randomized Design, what does the term 'treatment' refer to?
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Which of the following is NOT a characteristic of a Complete Randomized Design?
Which of the following is NOT a characteristic of a Complete Randomized Design?
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How does randomization in experimental design help mitigate bias?
How does randomization in experimental design help mitigate bias?
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What is the primary purpose of blocking in experimental design?
What is the primary purpose of blocking in experimental design?
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Which of the following describes replication in experimentation?
Which of the following describes replication in experimentation?
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What is the risk of confounding variables in an experiment?
What is the risk of confounding variables in an experiment?
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How does randomization affect statistical significance in an experiment?
How does randomization affect statistical significance in an experiment?
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What is the main goal of stratified random sampling?
What is the main goal of stratified random sampling?
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What does control of variables entail in an experiment?
What does control of variables entail in an experiment?
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What is the significance of random assignment in experimental design?
What is the significance of random assignment in experimental design?
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What defines sample size in the context of an experiment?
What defines sample size in the context of an experiment?
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Study Notes
Completely Randomized Design (CRD)
- CRD: A type of experimental design where experimental units are randomly assigned to different treatments or conditions.
- This approach minimizes bias, enabling generalization of results.
- Experimental units, like plants, animals, or subjects, are randomly assigned to different treatments or conditions.
Definition of Terms
Randomization
- Definition: The process of assigning experimental units to different treatments or conditions randomly.
- This practice minimizes the influence of confounding variables, ensuring results are due to the treatment effect, not other systematic biases.
Randomized Control Trial (RCT)
- Definition: A type of experimental design assigning participants randomly to either a treatment or control group.
- RCTs are considered the gold standard in experimental research because random assignment controls for confounding factors.
Experimental Unit
- Definition: The smallest unit of observation in an experiment.
- This receives the treatment or intervention (e.g., single plant in agriculture).
Treatment
- Definition: A specific intervention, condition, or procedure applied to experimental units.
- Can include a drug, educational program, or different manufacturing process.
Control Group
- Definition: A group of experimental units not receiving the treatment being tested, but rather a placebo, no treatment, or standard treatment.
- Used for comparison, determining the effect of the experimental treatment.
Random Effects
- Definition: Factors in a model assumed random, drawn from a probability distribution.
- These factors represent sources of variability not of primary interest but contribute to the overall variability in data (e.g., individual differences).
Block Design
- Definition: An experimental design grouping experimental units into similar blocks.
- Treatments are randomly assigned within each block. This helps control variability between blocks, making the experiment more precise.
Replication
- Definition: Repeating an experimental condition or treatment within an experiment.
- Replication increases the reliability of results and allows for better estimation of variability.
Bias
- Definition: Systematic errors in design, data collection, or analysis leading to inaccurate or skewed results.
- Randomization helps reduce bias by ensuring treatments are assigned without bias.
Confounding Variables
- Definition: Variables related to both the treatment and the outcome, potentially distorting the observed relationship between them.
- Randomization helps minimize confounding by evenly distributing confounding variables across treatment groups.
Statistical Significance
- Definition: A statistical measure determining if observed effects in an experiment are due to chance or reflect a true relationship.
- Randomization increases the likelihood that statistical tests assess the significance of treatment effects correctly.
Stratified Random Sampling
- Definition: A sampling method dividing a population into subgroups (strata) based on characteristics.
- Random samples are drawn from each stratum. This ensures relevant subgroups are represented in the sample.
Control of Variables
- Definition: Keeping all variables constant except the independent variable being tested.
- Randomization helps control potentially confounding variables.
Random Assignment
- Definition: Assigning subjects or experimental units to different treatments randomly (using a random number generator).
- Ensures each subject or unit has an equal chance of being assigned to any group.
Sample Size
- Definition: The number of experimental units or subjects in an experiment.
- A larger sample size improves the precision of estimates and statistical tests' power.
Sampling Error
- Definition: The difference between a sample estimate and the true population value.
- Random sampling reduces sampling error by ensuring the sample represents the population.
Double-Blind Experiment
- Definition: An experimental design where neither participants nor experimenters know which treatment participants are receiving.
- This prevents bias in treatment administration and outcome measurement.
Placebo Effect
- Definition: A psychological phenomenon in which participants experience improvements simply because they believe they're receiving treatment.
- A placebo group measures this effect.
Factorial Design
- Definition: An experimental design testing multiple factors (independent variables) simultaneously to examine their individual and interactive effects on an outcome.
- Random assignment is often used to reduce bias.
True Experimental Design
- Definition: An experimental design using random assignment to treatment groups and controlled conditions to determine cause-and-effect relationships.
- Contrasts with quasi-experimental designs, lacking randomization.
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Description
Explore the concept of Completely Randomized Design (CRD) and its importance in experimental research. This quiz covers definitions related to randomization, randomized control trials, and experimental units, highlighting how random assignment minimizes bias and enhances the validity of results.
