is a subset of a statistical population
in which each member of the subset
has an equal probability of being
chosen.
Ex: write some names in pieces of paper
and put in a bowl and (without looking)
choose 3
SYSTEMATIC
SAMPLING
is a probability sampling
method where researchers
select members of the
population with an interval.
Ex:in a group of 12 people
select a person every third
STRATIFIED SAMPLING:
involves the division of a population into
smaller sub-groups known as strata.
STRATIFIES RANDOM
SAMPLING
this method consist in
divide the polpulation in
strats like Age,
socioeconomic divisions,
nationality, religion,
educational level and
other , and take a
sampling.
Ex: suppose you are trying to take
a sample of students to ask them
whether or not they support a
new parking lot at the school.
Certainly Freshman students will
have different support levels than
Seniors, so you must Take the
population of all high school
students at your school and split
them into groups (strata) by
grade level. Take an SRS of 25
students from each grade level.
STRATIFIES SYSTEMATIC
SAMPLING
this method is abot divide
the polulation in subgroups
too, but the saple is
selected with an interval
EX: Let’s consider a
situation where a
research team is
seeking opinions about
religion amongst
various age groups.
citizens can be divided
into strata according to
age, groups of 18-29,
30-39, 40-49, 50-59, and
60 and above. In every
group you going to
select a person every
4th person .
Selecting the elements randomly
NON-PROBABILISTIC
CONVENIENCE
SAMPLING
involves collecting samples from
the population that is closer to
the researcher,but that sample
is not taken under
consideration the entire
population.
A example of a convenience sampling
method is when companies distribute
their promotional pamphlets and ask
questions at a mall or on a crowded
street with randomly selected
participants.
QUOTA SAMPLING
is a sampling methodology
wherein data is collected from a
homogeneous group, can be
used to filter information from
the population, in a quota
sampling there is a non-random
sample selection taken, but it is
done from one category , so the
researchers run the risk of bias.
A company
wants to find
out who
consumes the
most perfume
so it divides its
customers into
two groups:
men and
women and
calculates the
relative
percentages of
both.
JUDGEMENT SAMPLING
Is when one individual or
a group of individuals
choose who and who not
to include in the sample.
Although the individuals
chosen for this
assignment are
considered experts,
views and insight which
might not reflect the
real-world population.
EX: TV reporters stopping
certain individuals on the
street in order to ask their
opinions about certain
political changes. However, it
is important to specify that
the TV reporter has to apply
certain judgment when
deciding who to stop on the
street to ask questions;
otherwise it would be the
case of random sampling
technique.