1-1
Populations and Samples
Warm Up
Problem of the Day
Lesson Presentation
Course 2
1-1 Populations and Samples
Warm Up
Simplify.
1. 72  10 720
2. 26 + 75 101
3. 127  34 93
4. 125  25 5
5. 1,234 + 843 2,077
6. 851  653 198
7. 43  12 516
8. 657  3 219
Course 2
1-1 Populations and Samples
Problem of the Day
Why are both products the same?
26  51 = 1,326
39  34 = 1,326
26  51 = (2  13)  (3  17);
39  34 = (3  13)  (2  17);
the factors are 2, 3, 13, and 17
Course 2
1-1 Populations and Samples
Learn to identify populations and random
samples.
Course 2
1-1 Populations and Samples
Vocabulary
population
sample
random sample
Course 2
1-1 Populations and Samples
A population is the whole or entire
group.
A sample is a smaller group of
people or objects chosen for study
from a larger group or population.
Course 2
1-1 Populations and Samples
When scientists track migratory animals, they
cannot track each animal. Instead, they tag a
sample of the population and track the sample.
They use the sample to gather statistical data
about the population.
Course 2
1-1 Populations and Samples
Additional Example 1A: Identifying Populations and
Samples
Identify the population and sample in the
situation.
A. The mayor surveys 1,000 voters to see
if they approve of the job she is doing.
Population
Sample
All registered voters 1,000 voters who are surveyed
Course 2
1-1 Populations and Samples
Additional Example 1B: Identifying Populations and
Samples
Identify the population and sample in the
situation.
B. The coach wants to know which uniform
the basketball team wants to wear, but
he only asks the starting five.
Population
Sample
The basketball team The starting five
Course 2
1-1 Populations and Samples
Additional Example 1C: Identifying Populations and
Samples
Identify the population and sample in the
situation.
C. The local movie theater surveys customers
to find out which brand of popcorn
customers prefer.
Population
Sample
All customers
Customers who respond to survey
Course 2
1-1 Populations and Samples
Try This: Example 1A
Identify the population and sample in the
situation.
A. A teacher surveys 50 students in the seventh
grade to find out the types of movies seventh
graders like.
Population
All seventh graders
Course 2
Sample
50 students who are surveyed
1-1 Populations and Samples
Try This: Example 1B
Identify the population and sample in the
situation.
B. A scientist studying corn production measures
the amount of corn produced by one acre of
corn plants.
Population
Sample
All corn plants one acre corn
Course 2
1-1 Populations and Samples
Try This: Example 1C
Identify the population and sample in the
situation.
C. A magazine surveys its subscribers to ask
what articles they liked in the latest issue.
Population
Sample
All subscribers The subscribers who answer the survey
Course 2
1-1 Populations and Samples
For a sample to be useful, it must be
representative of the population. If it is not,
then the information gathered from the
sample will be inaccurate.
One type of representative sample, known
as a random sample, gives every member
of the population an equal chance of being
chosen.
Course 2
1-1 Populations and Samples
Additional Example 2A: Identifying Random Samples
A teacher questions students about which day
to give a math test. Tell whether each
sampling method is random. Explain your
answer.
A. The teacher asks the first five students
who walk into the classroom.
This sampling method is not random. All
students not in the room at the time have no
chance of being chosen.
Course 2
1-1 Populations and Samples
Additional Example 2B: Identifying Random Samples
A teacher questions students about which day
to give a math test. Tell whether each
sampling method is random. Explain your
answer.
B. The teacher writes the name of each
student on a piece of paper and questions
the students whose names are drawn.
This sampling method is random. Each
student has an equal chance of being chosen.
Course 2
1-1 Populations and Samples
Additional Example 2C: Identifying Random Samples
A teacher questions students about which day
to give a math test. Tell whether each
sampling method is random. Explain your
answer.
C. The teacher questions the students in the
first desk in each row.
This sampling method is not random.
Students not in the first desk do not have a
chance of being chosen.
Course 2
1-1 Populations and Samples
Try This: Example 2A
The owner of a chain of record stores is
conducting a survey about the kind of music
his customers like. Tell whether each
sampling method is random.
A. The owner of the chain surveys only
customers over the age of 18 who shop
at his store.
This is not random. Customers under the age
of 18 do not have a chance of being chosen.
Course 2
1-1 Populations and Samples
Try This: Example 2B
The owner of a chain of record stores is
conducting a survey about the kind of music
his customers like. Tell whether each
sampling method is random.
B. The owner randomly selects 200
customers from a list of all his customers.
This sampling method is random. Each
customer has an equal chance of being
chosen.
Course 2
1-1 Populations and Samples
Try This: Example 2C
The owner of a chain of record stores is
conducting a survey about the kind of music
his customers like. Tell whether each
sampling method is random.
C. The owner surveys customers whose last
names begin with the letter r.
This sampling method is not random.
Customers whose last names do not begin
with the letter r do not have a chance of being
chosen.
Course 2
1-1 Populations and Samples
Lesson Quiz: Part 1
1. A TV ratings service is surveying
residents of Orlando who bought TVs in the
last month about their favorite TV show.
A. Identify the sample.
people who bought TVs in the last month
B. Identify the population.
all residents of Orlando
Course 2
1-1 Populations and Samples
Lesson Quiz: Part 2
2. The school newspaper is conducting a
survey on the students’ favorite subjects.
Tell whether each sampling method is
random. Explain your answers.
A. The newspaper surveys senior students in
a math class.
No; only seniors are being surveyed.
B. The newspaper surveys every twentieth
student entering the school.
No; not every student entering the school has a
chance to be chosen.
Course 2