Sampling Design

SAMPLE DESIGN The way of selecting a sample from a population is known as sample design. It describes various sampling techniques and sample size. It refers to the technique or procedure the researcher would adopt in selecting items for the sample.

STEPS IN SAMPLE DESIGN
• Type of universe
• Sampling unit
• Source List
• Size of Sample
• Parameters of Interest
• Budgetary Constraint
• Sampling Procedure

CRITERIA OF SELECTING A SAMPLING PROCEDURE
• Inappropriate sampling frame
• Defective measuring device
• Non-Respondents
• Indeterminancy principle
• Natural bias in the reporting of data

CHARACTERISTICS OF A GOOD SAMPLE DESIGN
• Sample design must result in a truly representative sample.
• Sample design must be such which results in a small sampling error.
• Sample design must be viable in the context of funds available for the research study.
• Sample design must be such so that systematic bias can be controlled in a better way.
• Sample should be such that the results of the sample study can be applied, in general, for the universe with a reasonable level of confidence.

Different types of sample designs

There are different type of sample designs based on two factors, the representation basis and the element selection technique. On the representation basis the sample may be probability sampling or it may be non probability sampling. Probability is based on random selection, whereas non probability sampling is ‘non-random sampling'. On element selection basis it can be unrestricted or restricted sample. Thus The following chart exhibits the sample designs:

CHART SHOWING BASIC SAMPLING DESIGNS

ELEMENT SELECTION TECHNIQUE

UNRESTRICTED SAMPLING

REPRESENTATION BASIS

PROBABILITY SAMPLING NON-PROBABILITY SAMPLING

SIMPLE RANDOM SAMPLING
HAPHAZARD SAMPLING OR CONVENIENCE SAMPLING