Page 150 - DMGT209_QUANTITATIVE_TECHNIQUES_II

Unit 8: Sampling and Sampling Distribution

(5) Determine the sample size: This means we need to decide “how many elements of the Notes
target population are to be chosen?” The sample size depends upon the type of study that
is being conducted.

Example: If it is an exploratory research, the sample size will be generally small. For
conclusive research, such as descriptive research, the sample size will be large.
The sample size also depends upon the resources available with the company. It depends
on the accuracy required in the study and the permissible errors allowed.
(6) Specify the sampling plan: A sampling plan should clearly specify the target population.
Improper defining would lead to wrong data collection.

Example: This means that, if a survey of a household is to be conducted, a sampling plan
should define a “household” i.e., “Does the household consist of husband or wife or both ”,
minors etc., “Who should be included or excluded”. Instructions to the interviewer should
include “How he should obtain a systematic sample of households, probability sampling non–
probability sampling”. Advise him on what he should do to the household, if no one is available.
(7) Select the sample: This is the final step in the sampling process.

Self Assessment

Fill in the blanks:

1. ........................ is the process of selecting units from a population of interest.
2. A sample is a part of a ........................ population.
3. Sampling ........................ is the list of elements from which the sample is actually drawn.

4. A census is appropriate if the size of population is ........................ .
5. A sampling plan should clearly specify the ........................ population.
6. The sample size depends upon the ........................ available with the company.

8.3 Types of Sample Design

Sampling is divided into two types:

 Probability sampling: In a probability sample, every unit in the population has equal
chances for being selected as a sample unit.
 Non–probability sampling: In the non-probability sampling, the units in the population
have unequal or negligible, almost no chances for being selected as a sample unit.

8.3.1 Probability Sampling Techniques

1. Random sampling.
2. Stratified random sampling.
3. Systematic sampling.

4. Cluster sampling.
5. Multi-stage sampling.

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