Sampling Methods
Sampling Methods
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Convenience – use the easiest group you
have access to
Random – Picked by a random method
Systematic – pick every kth person
Stratified – Separate according to
characteristics – then pick some from each
group (a few from all)
Cluster – pick all from a couple of groups (all
from a few)
What type of sampling
method is used?
Each student puts a number in the hat
and then a drawing is held.
Random Sampling
Survey statistics students to see if they
had enough time to take the test. We
randomly pick some of the schools that
took the test & every student at the
selected schools are surveyed.
Cluster Sampling
Put a big ad in the newspaper asking
people to log their opinions on the PTA
web site.
Convenience Sampling
Randomly select one of the elementary
schools and contact every parent by
phone.
Cluster Sampling
Send a survey home with every student,
and ask parents to fill it out and return
it the next day.
Convenience Sampling
Randomly select 20 parents from each
elementary school. Send them a
survey, and follow up with a phone call
if they do not return the survey within a
week.
Stratified Sampling
Hold a PTA meeting at each of the 20
elementary schools and tally the
opinions expressed by those who attend
the meetings.
Stratified Sampling
Go through the district’s enrollment
records, selecting every 40th parent.
PTA volunteers will go to those homes
to interview the people chosen.
Systematic Sampling
Randomly select two members from each
baseball team in the league to
represent the city all-star team.
Stratified Sampling
Homework
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Worksheet