I am HAFIZ M WASEEM FROM mailsi vehari BSc in science college Multan Pakistan MSC university of education Lahore Pakistan i love Pakistan and my teachers

1. HAFIZ
MUHAM
MAD
WASEEM
BA BA G
LAHORE
Micrometry

2. Advanced Analytical Techniques
UNIVESITY OF EDUCATION
LAHORE PAKISTAN

3. 3
 A population is a group of
organisms belonging to same
species which can interbreed
 or generally a group of people
under study
 There is rarely enough time or
money to gather information
from everyone or everything in
a population
 The purpose is to find a
representative sample (or
subset) of that population for
the study
Population and sample

4. 4
 A sample is a small
portion of a population
which is selected for the
study
 It is costly and time
consuming to carry out
research on the whole
population
 It must be representative
of the whole population
under study
 It helps us to derive
estimates and inferences
Population and sample

5. 5
 Larger sample sizes are more
accurate representations of
the whole population
 The goal is to
make inferences/conclusions
about a population
 The sample size chosen is a
balance between obtaining a
statistically valid
representation, and the
time, energy, money, labor,
equipments and access
available
Population and sample

6. 6
 A sampling frame is
complete list of all people
or organisms or items
which form the
population
 All members of the
population must be
present only once in the
frame
 No elements from outside
the population should be
included in the frame
Population and sample

8. 8
 A shortcut method for
investigating a whole
population
 A process in which a
predetermined number of
observations are taken from a
larger population to estimate
features of the whole
population
 Data is gathered on a small
part of the whole parent
population or sampling frame,
and used to see how the
picture look like
Sampling and sampling criteria

9. 9
 List of characteristics which
are decided before which are
essential for eligibility to form
part of the sample
 The purpose is to look at what
we are studying for our
research project
 It should include
◦ The minimum of biasness
◦ Normal distribution of
Parent population
◦ A 95% probability or
confidence level
Sampling and sampling criteria

10. 10
 In reality there is simply not
enough sources like
◦ Time
◦ Energy
◦ Money
◦ Labor/manpower
◦ Equipments
◦ Access to suitable sites to
measure every single item
 Therefore an appropriate
sampling strategy is adopted
to obtain a representative,
and statistically valid sample
of the whole population
Sampling and sampling criteria

12. 12
 Probability sampling:
◦ Sample has a known probability
of being selected
◦ Types include simple random,
systematic, stratified, cluster,
multistage sampling
 Non-probability sampling:
◦ Sample does not have known
probability of being selected as
in convenience or voluntary
response surveys
◦ Types include convenience
sampling, quota
sampling and purposive
sampling
Types of sampling

13. 13
 Least biased of all
sampling techniques
 Each member of the total
population has an equal
chance of being selected
 It provides greatest
number of possible
samples
 Applicable when
population is
• Small
• Homogeneous
• Readily available
Types of sampling

14. 14
 Advantages
◦ Estimates are easy to
calculate
◦ Simple random sampling is
always an EPS design, but
not all EPS designs are
simple random sampling
 Disadvantages
◦ Impracticable with large
sampling frame
◦ Minority subgroups of
interest in population may
not be present in sample in
sufficient numbers for the
study
Types of sampling

15. 15
 The samples are chosen in a
systematic or regular way
◦ They are evenly distributed
in a spatial context for
example every two meters
along a transect line
◦ They can be at
equal/regular intervals in a
temporal context for
example every half hour or
at set times of the day
◦ They can be regularly
numbered for
example every 10th house
or person
Systematic sampling

16. 16
 Advantages:
◦ Easy to select
◦ Suitable sampling frame can
be identified easily
◦ Samples evenly spread over
entire reference population
 Disadvantages:
◦ Sample may be biased if
hidden periodicity in
population coincides with
that of selection.
◦ Difficult to assess precision
from one survey.
Types of sampling techniques

17. Advanced Analytical Techniques

18. 18
 The defining characteristic is to
get representative data from a
group
 This is generally done to ensure
the inclusion of a particular
segment of the population
 The proportions may or may not
differ dramatically from the
actual proportion in the
population
 The researcher sets a quota,
independent of population
characteristics
 It is based on the proportion of
subclasses in the population
Nonprobability Sampling

19. 19
 It is sampling which is more
accessible and proximal for the
researcher
 It may not be even
representative of the entire
population
 It is fast, expensive and easy
method
 We get the basic data,
informations and trends
 Volunteers constitute a
convenience sample.
 It may be biased by volunteers
Nonprobability Sampling