Methods of Probability sampling

1. By
A. Raja
SUBJECT: Business Research Methods
TOPIC : Sampling , Types of Probability Sampling

2. Sampling:
A sample is “a smaller collection of units from a
population, used to determine truths about that
population”.
When the data is to be collected from each
member of the population it is known as census survey.
When the data is to be collected from some
members of the population it is known sample survey.

3. Classification of Sampling Methods:
 Probability sampling is a sampling technique, where
the samples are gathered in a process that gives all the
individuals in the population, equal chances of being
selected.
Probability Sampling Non-Probability Sampling
Methods of Sampling

4. Types of Probability Sampling:
 Simple random sampling
 Systematic sampling
 Stratified Random sampling
 Cluster (area) sampling

5.  Simple random sampling(Random sampling):
It is the easiest form of probability sampling. In it
each unit of the population has equal chance of being
included in the sample.
This method implies that if
N = Size of the population
n = Units are to be drawn in the sample, then
the sample should be taken in such a way that each of the
Ncn samples has an equal chance of being selected.

6.  Systematic Random Sampling:
In this sampling , one unit is selected at random from the
universe and the other units are at a specified interval from the
selected unit . This method is used when the population is finite
and the units in the Universe can be arranged on the basis of an
system like alphabetical arrangement , numerical arrangement or
geographical arrangement.

7.  Stratified Random Sampling:
A method of sampling that involves the division of a population
into smaller groups known as strata and Random samples can be
taken from each strata or group.

8. Cluster sampling : In this technique, the total population is
divided into the groups (or clusters) and a simple
random sample of the groups is selected.