Experimental Research Overview of Experimental Research Traditional type

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Experimental Research

Experimental Research

Overview of Experimental Research • Traditional type of research • Purpose is to investigate

Overview of Experimental Research • Traditional type of research • Purpose is to investigate cause-and-effect relationships among variables – Experimental groups vs. control groups – Each group of participants receives a different treatment – Always involves manipulation of the independent variable • Answers the question “What will be? ”

Systematic Procedures • More than any other type of research, experimental research should follow

Systematic Procedures • More than any other type of research, experimental research should follow a definite, orderly procedure • Specific steps follow. . .

Research Validity • Internal Validity – the validity of findings with the research study;

Research Validity • Internal Validity – the validity of findings with the research study; the technical soundness of a study, particularly concerned with the control of extraneous influences that might effect the outcome • External Validity – the degree to which the findings can be inferred to the population of interest or to other populations or settings; the generalizability of the results • Both are important in a study but they are frequently at odds with one another in planning and designing a study • Internal validity is considered the basic minimum for experimental research

What is an experimental design? • An experiment is a process or study that

What is an experimental design? • An experiment is a process or study that results in the collection of data. • Usually the experiment is designed by researchers who can manipulate the conditions of the experiment and can control the factors that are irrelevant to the research objectives.

Parts of an experimental design Experimental designs must first have a problem or a

Parts of an experimental design Experimental designs must first have a problem or a question that can be testable and data can be collected. Experiments must have variability and validity. (Mc. Millan & Wergin pp. 61 -62, 2010) The researcher often has a hypothesis such as an “if” question; (E. C. Scott, 2004) “If skin cancer is related to ultraviolet light, then people with a high exposure to UV-light will have a higher rates of skin cancer. ”

Key Components of Experimental Design • Once the researcher has the hypothesis then he/she

Key Components of Experimental Design • Once the researcher has the hypothesis then he/she must form an experiment that has the following: • Independent variable • Dependent variable • Control group or constant • Results • Conclusion based on the results • These are the main parts but an experiment is not limited to these few.

Terms Defined • Hypothesis: is a proposition or a theory that one is trying

Terms Defined • Hypothesis: is a proposition or a theory that one is trying to verify, in this case through experiment. • Independent Variable: the variable in an experiment that can be changed or manipulated (input or causes). This can also be what is tested to see if it is the cause of the expected effect. • Dependent Variable: the variable in an experiment that is being measured (output or effect) and is dependent upon the other variables.

Terms Defined cont… • Experimental Group and Control Group: the experimental group is the

Terms Defined cont… • Experimental Group and Control Group: the experimental group is the group that receives the treatment and the control group is the group that does not receive the treatment. • Error Variable: are the variables that are not controlled like the independent variable that can cause effects in the depend variable. • Results: the outcome of the experiment that was performed on the groups.

Evaluation Criteria for Experimental Design • According to Mc. Millian and Wergin, there nine

Evaluation Criteria for Experimental Design • According to Mc. Millian and Wergin, there nine specific criteria for evaluating experimental studies:

General Purpose of Study Mc. Millan, J. H, & Wergin, J. F. (2010) 1.

General Purpose of Study Mc. Millan, J. H, & Wergin, J. F. (2010) 1. The purpose of the study is clear and concise. The research material gathered from the study will contribute to specific interpretations

The Research Connection Mc. Millan, J. H, & Wergin, J. F. (2010) 2. The

The Research Connection Mc. Millan, J. H, & Wergin, J. F. (2010) 2. The research should suggest a relationship between other studies to the most current study. The current research corresponds to other similar studies.

Research Method Clear and Concise Mc. Millan, J. H, & Wergin, J. F. (2010)

Research Method Clear and Concise Mc. Millan, J. H, & Wergin, J. F. (2010) 3. The hypothesis (educated guess) is clearly stated.

How Was the Method Sampled? Mc. Millan, J. H, & Wergin, J. F. (2010)

How Was the Method Sampled? Mc. Millan, J. H, & Wergin, J. F. (2010) 4. The research method sample should be documented and described in depth.

What Are the Variables? Mc. Millan, J. H, & Wergin, J. F. (2010) 5.

What Are the Variables? Mc. Millan, J. H, & Wergin, J. F. (2010) 5. The variables should be defined.

Define Data Collection Procedures Mc. Millan, J. H, & Wergin, J. F. (2010) 6.

Define Data Collection Procedures Mc. Millan, J. H, & Wergin, J. F. (2010) 6. What types of data collection was used?

Internal and External Validity Mc. Millan, J. H, & Wergin, J. F. (2010) 7.

Internal and External Validity Mc. Millan, J. H, & Wergin, J. F. (2010) 7. All possible external and internal factors are reviewed

Limitations of the Study Mc. Millan, J. H, & Wergin, J. F. (2010) 8.

Limitations of the Study Mc. Millan, J. H, & Wergin, J. F. (2010) 8. The study draws specific conclusions and implications and also describes limitations in the study that may effect specific outcomes.

The Findings Can Be Generalized Mc. Millan, J. H, & Wergin, J. F. (2010)

The Findings Can Be Generalized Mc. Millan, J. H, & Wergin, J. F. (2010) 9. The findings address an approach to generalize the research procedures.

Your turn! Read to following experiment and see if you can identify the main

Your turn! Read to following experiment and see if you can identify the main components of experimental design.

 • A researcher is curious to find out what effect classical music has

• A researcher is curious to find out what effect classical music has on people’s level of relaxation (as measured by heart rate). He suspects that listening to classical music will make people feel more calm and relaxed. He lets one group listen to classical music for one hour. He lets another group sit in a quiet room for one hour (i. e. they hear no music). After one hour, he monitors the heart rate of each participant to measure their level of relaxation.

What are… • Independent variable: • Dependent variable: • Experimental group: • Control group:

What are… • Independent variable: • Dependent variable: • Experimental group: • Control group: