From a class of 25 students the
teacher selects the last 5 to
enter the room.
A professor numbers his
students from 1 to 200, places
those numbers in a hat, mixes
thoroughly and chooses 6
numbers without looking.
From a group of 100 employees,
the manager randomly selects 12
of the 60 women and 8 of the 40
men to form a sample of 20.
In a class of 12 boys and 12
girls a teacher selects 5
students by numbering the boys
01 to 12 and the girls 13 to 24
and uses a random number table
to choose 5 numbers between 01
and 24.
In a movie queue an interviewer
select the fifth person at
exactly 1:00 pm to ask
questions about their movie
preferences. She then selects
every 20th person in queue for
questioning.
The Director of High School
Education for a school district
randomly selects three of the
20 elementary schools in the
district and sends a survey to
the parents of each student in
the school.
A high school principal decides
to conduct a survey of the
senior class by selecting five
English 12 classes and
interviewing each student in
that class
A researcher wants to determine the
reading level of seniors in the
state of Pennsylvania. The
researcher obtains a list of all the
high schools in the state (public,
private, and on‐ line) and randomly
chooses 100 of those high schools.
She then administers a reading test
to all those students in those 100
high schools.
Simple Random Sample
Convenience Sample
Simple Random Sample
Stratified Random
Sample
Cluster Sample
Systematic Sample
Cluster Sample
Cluster Sample
A teacher wants to look back over
a test that she has given every
year for the past 10 years and
determine if students incorrectly
answered a certain question. She
has over 300 tests and wants to
have a sample of about 30 tests.
Since the tests are in no
particular order, the teacher
decides to look at every 10th test
in the stack.
In order to determine the average
cost of a hospital stay, a
hospital administrator obtains a
list of patients discharged from
its facility over the past year.
The administrator divides the
patients according to length of
hospital stay (3 days or less, 37 days, 8-14 days, more than 14
days) then selects a random
sample of 70 patients from each
group.
A librarian obtains a spreadsheet
of all books currently on the
library inventory. Using the
spreadsheet row numbers, he uses
a random number table to obtain a
sample of 500 books to determine
the average age of the library’s
collection of books.
To determine if average home
prices differs among geographic
regions, researchers use current
real estate listings to randomly
choose 500 homes for sale from
each time zone.
At the beginning of the year, a
large mail-order company decides
to send a customer satisfaction
survey to every 500th order that
they mail out.
A national polling organization
uses ‘random digit dialing’ and
calls 1500 households in order to
determine current Presidential
approval ratings.
Each of the 29 NBA teams has 12
players. A sample of 58 players
is to be chosen as follows. Each
team will be asked to place 12
cards with their players' names
into a hat and randomly draw out
two names. The two names from
each team will be combined to
make up the sample.
To survey the opinions of
bleacher fans at Wrigley Field, a
surveyor plans to select every
one hundredth fan entering the
bleachers one afternoon.
Stratified Random
Sample
Systematic Sample
Stratified Random
Sample
Simple Random Sample
Simple Random Sample
Systematic Sample
Systematic Sample
Stratified Random
Sample
A state auditor is given an
assignment to choose and audit 26
companies. She lists all
companies whose name begins with
A, assigns each a number, and
uses a random number table to
pick one of these numbers and
thus one company. She proceeds to
use the same procedure for each
letter of the alphabet and then
combines the 26 results into a
group for auditing.
A researcher planning a survey of
heads of households in a
particular state has census lists
for each of the 23 counties in
that state. He plans to gather a
random sample of heads of
households from each of the
counties.
To conduct a survey of longdistance calling patterns, a
researcher opens a telephone book
to a random page, closes his
eyes, puts his finger down on the
page, and then reads off the next
50 names.
In the classroom, students are
seated at tables. The teacher
selects one table at random and
samples all of the students at
that table.
In a large suburban high school,
the administration decides to
poll the student body by randomly
selecting 3 departments (Math,
English, Arts, etc), then from
each of those department, the
administration selects 5 teachers
randomly. Finally, they randomly
select 5 students from the 3rd
hour class of each of those
teachers.
After the guests have departed, a
hotel sends an email to each
guest with a link to an online
survey in order to gather
information about the guest
satisfaction.
A teacher asks the class to
number off from 1 to 30, then
uses the random number generator
on the TI84 to select 3 students
to share a quick summary of the
day’s lesson.
In a large urban area, a polling
organization wishes to gather
information from the entire
metroplex. They decide to
randomly select 500 households
from the city and 100 households
from each suburb.
Stratified Random
Sample
Stratified Random
Sample
Cluster Sample
Cluster Sample
Voluntary Response
Sample
Multistage Sample
Stratified Random
Sample
Simple Random Sample
In order
for a
student
that sit
to gather information
science project, a
polls other students
nearby in each class.
Each night, the local TV
station has a flash poll
question, asking viewers to
call or text in their vote.
To determine support for a new
city initiative, the city
manager selects 10 city
neighborhoods at random, then
using an aerial map, selects 25
homes within each neighborhood
to be included in the sample.
A large hospital wants to
survey its recent patients to
determine the wait time in the
ER. The hospital administrator
generates a list of random
patient ID numbers from the ER
records of the past 6 months
and has his staff contact each
of the selected patients.
A school wants to encourage
more parent participation, so
they send home a survey with
each student asking the parents
to complete the survey and
return it to their child’s
teacher.
A survey on student study
habits was handed out to the
first 100 students to enter the
cafeteria at lunch.
A researcher randomly selects
25 files from each precinct of
an urban police department in
order to estimate the average
age of criminals.
A quality control officer for a
large grocery chain needs to
determine if a shipment of
fruit is suitable for purchase.
She selects the 3 pallets near
the door to inspect for
bruising and ripeness.
Voluntary Response
Sample
Convenience Sample
Simple Random Sample
Multistage Sample
Convenience Sample
Voluntary Response
Sample
Convenience Sample
Stratified Random
Sample