NURSING RESEARCH SAMPLING
it include following sub points-
1) terminologies related to sampling
2 definition of sample and sampling
3) advantages of sampling
4) sampling process
5) types of sampling (probability and non probability)
2. Introduction:-
Researcher rarely study the whole
population of subjects.
The safest choice is to study the whole
population.
www.vipinpatidar.wordress.com
3. terminology:-
POPULATION-
A complete set of persons or object that possess
some common Characterstics that is of interest to
the researcher.
It is the entire aggregation of cases that meet a
specified set of criteria.
www.vipinpatidar.wordress.com
KINDS OF POPULATION-
Theoretical population-
accessible population-
4. Contd…
THEORITICAL POPULATION-
The population you would like to generalize to
entire population in which researcher is
interested.
www.vipinpatidar.wordress.com
ACCESSIBLE POPULATION-
The population that will be accessible to
researcher.
5. terminology
PARAMETER-
The information or data collected from a
population called as parameter.
www.vipinpatidar.wordress.com
STATISTIC-
The information or data collected from a sample
called as statistic.
RANDOMIZATION-
It is the process of selecting a representation
sample of the target population ensuring that
every element in the target population has an
equal chance of being selected.
6. terminology
SAMPLING ERROR
It is difference or error between sample statistic
and the population parameters.
www.vipinpatidar.wordress.com
SAMPLING BIAS-
Occur when the researcher shows a preference in
selecting one participant over another.
SAMPLING CRITERIA-
The researcher needs criteria to determine
whether a person qualifies as a member of the
population.
7. terminology
SAMPLE-
Subset of population.
It is the finite part of a statistical population
whose properties are studied to gain information
about whole.
Webster 1985
www.vipinpatidar.wordress.com
SAMPLING-
It is the act, process or technology of selecting a
suitable sample or a representative part of a
population for the purpose of determining
characteristics of the whole population.
8. ADVANTAGES OF SAMPLING
The lower is cost/economy.
Timeless, data collection is faster.
To improve the accuracy and quality of
data.
Inaccessibility of some of the
population.
To avoid large size of population.
www.vipinpatidar.wordress.com
9. SAMPLING process
Define population
Theoretical population
Accessible population
Sampling frame
Sample selection
Determine sample size
Implement sampling plan
Reviewing the sampling process
www.vipinpatidar.wordress.com
10. Types of sampling / approaches:-
www.vipinpatidar.wordress.com
PROBABILITY NON PROBABILITY
• SIMPLE RANDOM
•STRATIFIED SAMPLING
•SYSTEMATIC SAMPLING
•CLUSTER SAMPLING
• PURPOSIVE SAMPLING
•QUOTA SAMPLING
•CONVENIENT SAMPLING
•SNOW BALL SAMPLING
11. 1) probability SAMPLING
1.1 SIMPLE RANDOM SAMPLING-
Each element in the population has an
equal and independent chance of being
chosen or selection.
www.vipinpatidar.wordress.com
13. 1) probability SAMPLING
1.2 STRATIFIED SAMPLING-
Divide population into groups (strata)
that differ in important ways .
Basis for grouping must be known
before sampling. E.g.- age, gender etc.
Select random sample from within each
group.
www.vipinpatidar.wordress.com
15. 1) probability SAMPLING
1.3 SYSTEMATIC SAMPLING-
Selecting every Kth element of
the population.
K=N/n K=sampling interval
N= total population
n= sample size
www.vipinpatidar.wordress.com
16. www.vipinpatidar.wordress.com
ADVANTAGES DISADVANTAGES
1) Fast, easy and
inexpensive.
1) Element in the
sampling frame must be
randomized.
2) Error may reduce
because of simplicity.
2) Complete list of target
population needed.
1.3 SYSTEMATIC SAMPLING-
17. 1) probability SAMPLING
1.4 CLUSTER SAMPLING-
Population is divided into large groups
(cluster).
Population
Cluster-1 cluster-2 cluster-3
Sample-1 sample-2 sample-3
www.vipinpatidar.wordress.com
19. 2) NON-probability SAMPLING
2.1 CONVENIENCE SAMPLING-
Subjects selected because it is easy to
access them.
No reason tied to purposes of research.
Students in your class, people on State
Street, friends.
www.vipinpatidar.wordress.com
21. 2) NON-probability SAMPLING
2.2 PURPOSIVE SAMPLING-
Subjects selected for a good reason
tied to purposes of research.
hand picking of subjects.
www.vipinpatidar.wordress.com
23. 2) NON-probability SAMPLING
2.3 QUOTA SAMPLING-
Pre-plan number of subjects in specified
categories (e.g. 100 men, 100 women).
The subjects chosen for those
categories are a convenience sample,
selected any way the interviewer
chooses
www.vipinpatidar.wordress.com
24. 2) NON-probability SAMPLING
2.4 SNOW BALL SAMPLING-
Initially contact a few potential
respondents and then ask them
whether they know of anybody with the
same characteristics.
www.vipinpatidar.wordress.com