The Research Design

Experimental Design

DefinitionA description of what a researcher would like to find out and how to find it out.

Pre-requisites1. Identification of problem2. Formulation of

hypothesis3. Detailed description and

explanation of the procedure of the experiment.

Experimental Procedure

1. Selection of appropriate materials for the test.

2. Specification of the variable to be measured.3. Selection of procedure to be used to measure

the identified variables.4. Specification of the procedure that will be

used to test whether the data supports the hypothesis or not.

Research Design

DescriptionA complete sequence of steps or procedures that need to be followed when obtaining the required data during an investigation.

Significance of the Research Design• Serves as a guide during the

conduct of an experimental investigation

• Minimizes cost• Maximizes gained

information relevant to the problem

Research Design is…

embodied in a research proposal

Parts of a Research Proposal1. Introduction

1. Background of the Study2. Statement of the Problem3. Significance of the Study4. Scope and Limitations of the Study

2. Review of Related Literature3. Methodology4. Bibliography

Points to Remember

Subject–Also known as the experimental unit–May be a person, animal, plot, device, etc.–May be subjected to different treatments (experimental research) or to pure observation only (descriptive research)

Treatment–Any procedure done on an experimental unit

Principles of Research Design

Replication• Repetition• Allows estimating

variations among variations in the subject possible.

• Necessary to conduct statistical test of significance

Randomization• Assignment of

experimental subjects to treatments by chance.

• Done to create equivalent groups prior to the experiment

• Reduces possible biases

Principles of Research Design

Local Control• Grouping

subjects into blocks or units that are relatively homogeneous.

Control of Extraneous Variables• Ensures that identical

conditions are provided to the experimental and control groups except for the absence (control) and presence (experimental) of the treatments.

Types of Research Design

Completely Randomized Design (CRD)

• Treatments are assigned randomly to experimental subjects without restrictions

• Is used when the subjects are homogeneous• The loss of information due to missing

observation is small compared to other designs.

• Used in single-factor experiments

Randomized Complete Block Design

• Divides the experimental subjects into more or less homogeneous groups called designs.

• Appropriate when subjects can be categorize according to certain characteristics and when a few dropouts are expected.

• Used when randomization will tend to produce groups which are not nearly equivalent for comparison.