Chapter B (Survey Design) Flashcards
the population about which information is
ideally desired to get
Example: the collection of voters in the community
Target Population
the population from which a sample is actually taken (sampled population)
Example: the collection of registered voters in the community
Survey Population
a list of elements covering the target population
Example: list of registered voters in the community
Sampling Frame
A good sampling frame must possess the
following:
- Each unit must be counted and be counted only once and must be distinguishable from other units
- Up-to-date information should be provided
Illustrate Target Population vs. Survey Population
- Target Population:
A. Not included in the frame
B. Not eligible for survey, Not reachable, Refuse to respond
C. Not capable of responding
D. Survey Population - Sampling Frame
E. Not Eligible for Survey
an object on which a measurement is taken (element)
Example: a registered voter in the community
Observation Unit
Criteria for acceptability of a sampling method
▧ The sampling procedure should be easily
implemented and practical
▧ For statistical analysis, a sample must
represent the population and that reliability
must be measurable
Two Type of Sampling Methods
- Probability Sampling
- Non-probability Sampling
a procedure wherein every element of the
population is given a (known) nonzero chance of being selected in the sample
Probability Sampling
a procedure wherein not all the elements in the population are given a chance of being included in the sample
Non-Probability Sampling
Four Examples of Non-Probability Sampling
Purposive sampling, Convenience
sampling, Quota sampling, Snowball
sampling
▧ Probabilities of selection are not specified for the individual units of the population
▧ The researcher cannot assert that the
sample is representative of the larger
population (disadvantage)
Non-Probability Sampling
sets out to make the sample agree with the population regarding certain characteristics
(judgment sampling)
Purposive Sampling
A planning officer wants to determine the
perception of establishments about the possible road expansion in the area. He selected samples of establishments with the largest contributions to paying taxes.
Purposive Sampling
chooses units that come to hand or are
convenient (haphazard/accidental) sampling
Convenience Sampling
the sample has the same proportions of
individuals as the entire population concerning
known characteristics, traits, or focused
phenomenon
Quota Sampling
the sample selection is based on referrals from
initially sampled respondents to other persons
believed to have the same characteristics
(chain referral sampling)
Snowball Sampling
Used if the main objective of the sample
survey is MAKING INFERENCES about the
characteristics of the population under study
▧ It specifies rules and procedures for both
sample selection and estimation
Probability Sampling “yung mga random sampling”
Process of selecting a sample of size n giving
each sampling unit an equal chance of being
included in the sample
▧ Each subset of n SRS observations of the
population has the same chance of being
selected
▧ The selection of units uses some random
process like the lottery, via a random number
generator, etc.
Simple Random Sampling
▧ The population is divided or stratified, into
more or less homogeneous subpopulations or
strata before sampling is done
▧ then consists of
selecting an SRS from each of the strata into
which the population has been divided
Stratified Random Sampling
Formula of Equal Allocation
n / L
Formula of Proportional Allocation
(Ni / N) * n
The selection of samples involves taking
every kth unit from an ordered population
Sytematic Sampling
k is called the sampling interval and is
computed as ?
k = N / n
