Experimental Design Quiz: Test Your Knowledge in Research

Study Notes

Experimental Design in Practical Research

Definition

Experimental design refers to the plan and structure of an experiment, including the methods and procedures used to test a hypothesis.

Types of Experimental Designs

True Experimental Design:
- Involves random assignment of participants to treatment or control groups.
- Allows for causal inferences about the effect of the independent variable on the dependent variable.
Quasi-Experimental Design:
- Lacks random assignment of participants to groups.
- Can still establish causal relationships, but with limitations.
Pre-Experimental Design:
- Lacks a control group or random assignment.
- Often used in exploratory or pilot studies.

Key Components of Experimental Design

Independent Variable (IV):
- The variable being manipulated or changed by the researcher.
- Affects the dependent variable.
Dependent Variable (DV):
- The variable being measured or observed.
- Affected by the independent variable.
Control Group:
- A group that does not receive the treatment or intervention.
- Provides a baseline for comparison.
Treatment Group:
- A group that receives the treatment or intervention.
- Compares to the control group to measure the effect of the IV.

Threats to Internal Validity

Selection Bias:
- Occurs when the groups are not comparable at the outset.
- Can be addressed through random assignment.
Maturation:
- Occurs when participants change naturally over time.
- Can be addressed through control groups and longitudinal designs.
History:
- Occurs when external events affect the outcome.
- Can be addressed through control groups and statistical controls.
Testing:
- Occurs when the measurement tool affects the outcome.
- Can be addressed through multiple measures and controls.
Instrumentation:
- Occurs when the measurement tool changes over time.
- Can be addressed through standardized measures and controls.

Experimental Design Considerations

Sample Size:
- Affects the power and precision of the study.
- Should be determined based on the research question and population.
Randomization:
- Ensures that groups are comparable at the outset.
- Reduces confounding variables and bias.
Blinding:
- Prevents participants and researchers from knowing group assignments.
- Reduces bias and placebo effects.

Description

Understand the concepts of experimental design, types of designs, key components, threats to internal validity, and considerations in research. Learn about true experimental, quasi-experimental, and pre-experimental designs, and how to control for bias and confounding variables.