Let's break down the question about the type of educational research where variables are influenced and controlled. The question asks to identify the research type based on the characteristic that the variables under study are being influenced and controlled.

Understanding Research Types in Education

Educational research employs various methodologies to study teaching, learning, and other educational phenomena. Different types of research designs involve different levels of control and manipulation of variables.

Analyzing the Options

Let's examine each option in the context of the question's description:

• Quasi experimental research: This type of research involves manipulating or influencing an independent variable to observe its effect on a dependent variable. However, unlike true experimental research, participants are not randomly assigned to treatment groups. Instead, pre-existing groups are often used. While there is manipulation (influence), the control over extraneous variables is typically less robust than in true experiments due to the lack of randomization. However, researchers do employ other control techniques (like matching, statistical control). So, variables are influenced, and some level of control is attempted.
• Experimental research: This is often considered the gold standard for establishing cause-and-effect relationships. It involves manipulating an independent variable, and crucially, participants are randomly assigned to different treatment and control groups. This random assignment provides a high level of control over extraneous variables, ensuring that observed effects are likely due to the manipulated variable. In true experimental research, variables are both heavily influenced (manipulated) and rigorously controlled (via randomization and other methods).
• Ex-post facto research: Also known as causal-comparative research, this design examines the relationship between variables after the events have already occurred. The researcher does not manipulate or influence any variable. They look at existing conditions or past exposures and compare groups based on these pre-existing differences. There is no manipulation or control of variables by the researcher in the sense of intervention.
• Mixed research: This refers to a research approach that combines elements of both quantitative and qualitative research methods within a single study. It's a methodological approach focusing on data collection and analysis types, rather than a specific design defined by the manipulation and control of variables as described in the question.

Relating to "Influenced and Controlled"

The phrase "variables under study are being influenced and controlled" points towards research designs where the researcher actively intervenes or manipulates a variable (influence) and tries to manage other factors that could affect the outcome (control). Both experimental and quasi-experimental research involve influencing variables (manipulation). The difference lies primarily in the level of control, particularly through randomization.

In many real-world educational settings, conducting true experiments with random assignment can be difficult or impossible due to logistical, ethical, or practical constraints. Quasi-experimental designs are frequently used in education because they allow researchers to investigate interventions (influence variables) in natural settings where full experimental control isn't feasible. Despite lacking random assignment, researchers using quasi-experimental designs still implement control strategies to strengthen the validity of their findings.

Considering the context of educational research where quasi-experimental designs are common due to the reasons mentioned, and these designs involve influencing variables and applying control techniques (even without randomization), "Quasi experimental" aligns with the description provided in the question.

Based on the description that variables are influenced and controlled, and considering the nature and common application of research types in education, quasi-experimental research fits this description where manipulation occurs and control measures are applied, though typically not with the same rigor as true experimental designs.

Conclusion

The type of educational research described, where variables under study are being influenced and controlled, corresponds to Quasi experimental research, as it involves manipulation of variables and the application of control techniques, often within real-world educational settings.

Revision Table: Educational Research Designs

Additional Information: Control in Research

Control in research is crucial for establishing valid conclusions, particularly about cause-and-effect. Researchers aim to control for extraneous variables – factors other than the independent variable that could affect the dependent variable. In true experimental research, random assignment is a powerful control technique as it helps distribute potential confounding variables equally across groups. In quasi-experimental research, when random assignment isn't possible, researchers use alternative control methods like matching participants or groups on key characteristics, using pre-tests to measure baseline differences, or employing statistical techniques (like ANCOVA) to account for initial differences between groups. These methods help to enhance the internal validity of quasi-experimental studies, although they may not provide the same level of certainty as random assignment in true experiments.