A clear and defined concept of Non-Probability Sampling for the researchers. But, you mental cognition can produce the more best.

1. Non-Probability Sampling Techniques
Presented to: Dr. Intizar Hussain Butt
Presented By:
Anjum Zaman (142204)
Muhammad Umar farooq (142219)
Muhammad Usama (142220)
M.A Education (L & M) Evening Session (2014-2016)
DIVISION OF EDUCATION
UNIVERISTY OF EDUCATION, Lahore

2. Study Guide (Overview)
a) What is Population ?
b) What is Sample ?
c) What is Probability sampling ?
d) What is Non-probability sampling ?
e) What is Convenient sample ?
f) What is Quota sample ?
g) What is Judgment sample ?
h) What is Snowball sample ?

3. What is a Population?
DEFINITION:
The group to which you want to
generalize your findings.
IN OTHER WORDS:
The larger group you are representing with your
sample.
OR
The larger group to which your results will apply.

4. What is a Sample?
DEFINITION
A subset of the population being
studied from which data is actually
collected.
A good sample accurately represents all kinds
of elements/members in proportion to their
presence in the population.

5. Sampling Techniques
“Sampling techniques are the processes by which
the subset of the population from which you will
collect data are chosen”.
There are TWO general types of sampling
techniques:
1) PROBABILITY SAMPLING
2) NON-PROBABILITY SAMPLING

6. Non-Probability Sampling
DEFINITION
The process of selecting a sample
from a population without using
(statistical) probability theory.
NOTE THAT IN NON-PROBABILITY SAMPLING
 Each element/member of the population DOES NOT
have an equal chance of being included in the sample,
and
 The researcher CANNOT estimate the error caused
by not collecting data from all elements/members of the
population.

7. Example
Let's say that the university has roughly 10,000
students. These 10,000 students are our population
(N). Each of the 10,000 students is known as a unit,
but it’s hardly possible to get known and select
every student randomly.
So, here we can use Non-Random selection of sample
to produce a result, it is called sampling.

8. Why we use this Technique ? (Advantages)
In this technique the sampling process is
much easier, quicker and cheaper .
In this technique the sampling process is least time
consuming.
We use it, when randomization is impossible like
when the population is almost limitless.
Research does not aim to generate results that
will be used to create generalization pertaining
to the entire population.

9. Types of Non-Probability Sampling
1. Convenience Sampling
2. Quota Sampling
3. Purposive (Judgmental) Sampling
4. Snowball Sampling

10. Convenient Sampling
DEFINITION;
Selecting easily accessible participants
with no randomization.
For example;
In our example of the 10,000 university students, if we
were only interested in achieving a sample size of say
100 students. we may simply stand at one of the main
entrances to campus, where it would be easy to invite the
many students that pass by to take part in the research.
So, it is very easy (Convenient) to select.

11. SELECTION OF PARTICIPANTS
TYPE OF
SAMPLING
SELECTION
STRATEGY
PURPOSE
Convenience Select cases
based on their
availability for
the study.
Saves time,
money and
effort; but at
the expense of
information and
credibility.

12. Quota Sampling
DEFINITION
Selecting participant in numbers
proportionate to their numbers in the
larger population, no randomization.
For example ;
The number of students from each group that we would
include in the sample would be based on the proportion
of male and female students amongst the 10,000
university students. (Proportion; 50 male & 50 Female
or 40 Female & 60 Male)

13. SELECTION OF PARTICIPANTS
TYPE OF
SAMPLING
SELECTION
STRATEGY
PURPOSE
Quota; Select a sample
that yields the
same proportions
as the population
proportions on
easily identified
variables.
Taking a set
number of cases
from each
subgroup to raise
analytic
confidence and
representativeness
.

14. Purposive (Judgmental) Sampling
DEFINITION
Purposive sampling, also known
as judgmental, selective or subjective
sampling, reflects a group of sampling
techniques that rely on the judgment of the
researcher; when it comes to selecting the units
that are to be studied.
For Example Specific People, Specific
cases/organizations, Specific events, Specific
pieces of data)

15. SELECTION OF PARTICIPANTS
TYPE OF
SAMPLING
SELECTION
STRATEGY
PURPOSE
Purposive All cases that
meet some
criteria.
Useful for
quality
assurance.

16. Snowball Sampling
DEFINITION
Selecting participants by finding one or
two participants and then asking them
to refer you to others.
For example; Meeting a homeless person,
interviewing that person, and then asking
him/her to introduce you to other homeless
people you might interview.

17. SELECTION OF PARTICIPANTS
TYPE OF
SAMPLING
SELECTION
STRATEGY
PURPOSE
Snowball or chain
referral
Group members
identify additional
members to be
included in the
sample.
Identifies cases of
interest to people
who know people,
who know what
cases are
information-rich.

18. Drawbacks
The results Reliability cannot be measured in non-
probability sampling.
There is no assurance that the estimates (Judgment) will
meet an acceptable level of error.
This results in selection are biased.
Problem of non-representativeness.

19. THANK YOU All