Question

What do you know about experiment design? And mention the types.

Answer 1

An experiment design is a blueprint of the procedure that enables the researcher to test his hypothesis by reaching valid conclusions about relationships between independent and dependent variables. It refers to the conceptual framework within which the experiment is conduct.

A clear definition of the details of the experiment makes the desired statistical analyses

possible, and almost always improves the usefulness of the results. The overall data collection

and analysis plan considers how the experimental factors, both controlled and uncontrolled, fit

together into a model that will meet the specific objectives of the experiment and satisfy the

practical constraints of time and money.

Defining the experimental design consists of the following steps: 1. Identify the experimental unit. 2. Identify the types of variables. 3. Define the treatment structure. 4. Define the design structure.

Most experimental designs require experimental units to be allocated to treatments either randomly or randomly with constraints, as in blocked designs . Blocks are groups of experimental units that are formed to be as homogeneous as possible with respect to the block characteristics. The term block comes from the agricultural heritage of experimental design where a large block of land was selected for the various treatments, that had uniform soil, drainage, sunlight, and other important physical characteristics. Homogeneous clusters improve the comparison of treatments by randomly allocating levels of the treatments within each block. The design structure consists of those factors that define the blocking of the experimental units into clusters. The types of commonly used design structures are described next. Completely Randomized Design. Subjects are assigned to treatments completely at random. For example, in an education study, students from several classrooms are randomly assigned to one of four treatment groups (three new types of a test and the standard). The total number of students in 4 classrooms is 96. Randomly assign 1/4 of them, or 24 students, to each of the 4 types of tests.

A research design is an arrangement of types

• Descriptive , Correlational , Semi-experimental , Experimental , Review , Meta-analytic