# Experimental Design

**Topics:**Design of experiments, Experimental design, Experiment

**Pages:**7 (2469 words)

**Published:**January 20, 2013

By:

Yolanda M Harper

Instructor

Marciea McMillian-Robinson

Course

Research Methods

Date

July 30, 2012

Experimental Complex Design

An experiment involving an investigation of the effects of two or more independent variables, simultaneously, is referred to as a Complex Design. Two independent variables (IV), and one dependable variable (DV), constitutes the simplex complex design. The independent variable however, consists of two levels or conditions. The combination of independent variables included in an experiment to explain their effects on the dependent variables is referred to as Factorial Combination (Psychometrics: Complex Designs). The Complex Experimental Designs are of six types (Research Designs, 2012): •Factorial Design

•Solomon Four Group Design

•Repeated Measures Design

•Counterbalanced Measures Design

•Matched Subjects Design

•Bayesian Probability

Pairing of one independent variable in each level with other independent variable in each level is the base for factorials combining independent variables. A factorial design is known as “2x2 design”, when the four conditions occur in an experiment (Psychometrics: Complex Designs).

Purpose of Experimental Designs

A Factorial Design helps in the examination of the overall effects of one independent variable (say, Type of Writing), together with the overall effects of the other independent variable (say, Type of Instructions), as well as the combined effects of the two independent variables. This overall effect of an independent variable in a complex design is referred to as a main effect, and the overall effect of the independent variables in a complex design is known as interaction effect. It can be also defined as the only effect of the independent variable over the dependent variable, which makes an impression that only that variable was manipulated during the experiment. The interaction effect that occurs while the effects of an independent variable differ with regard to the level of the second independent variable (Psychometrics: Complex Designs). Either of the two independent variables could be manipulated using either independent groups design, or a repeated measures design, or both. Benefits of Experimental Designs

The main benefit underlying the complex design involves the experimental designs for testing hypotheses. The testing hypotheses could be achieved by controlling experimental factors, for predicting or establishing a result, that is based on the dependent and independent variables. This also provides a framework for a researcher, wherein he could carry out experiments to deny or confirm certain allegations. Providing cause effect relationships, providing helpful insights and offering reliable results are some of the other key benefits of the complex designs in an experiment. Investigators and researchers get adequate control for analyzing and establishing a cause-effect relationship through the experimental design. By carrying out experiments and implementing them, the researchers could analyze and reason for the unusual occurrences. The insight that has been provided by the experimental design is helpful in providing effective results to the concerned issues. For generating better results, the complex experimental designs provide quantitative measurement level utilization, procedures for allocation, random selection and controlled conditions, promoting high reliability of outcomes and also generating adequate results (Benefits of Experimental Design, 2012). Humanity's search for answers about the environment, culture, behavior, reactions on gases, and a lot more, is a continuous process. To come up with an accurate analysis, scientists and researchers have to be detailed and thorough on their procedures and experiments, namely the Experimental Complex Design. An experiment starts with an argument. What needs to be clarified? This is always the first process, to have a hypothesis. The...

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