1. Populations and Samples
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Populations and Samples
Warm Up
Problem of the Day
Lesson Presentation
Course 2

2. Populations and Samples
Course 2
1-1
Populations and Samples
Warm Up
Simplify.
1. 72 
720
101
  25 93 5
5. 1,  653
2,077
198
7. 43   3
516
219

3. Populations and Samples
Course 2
1-1
Populations and Samples
Problem of the Day
Why are both products the same?
26  51 = 1,  34 = 1,326
26  51 = (2  13)  (3  17);
39  34 = (3  13)  (2  17);
the factors are 2, 3, 13, and 17

4. Populations and Samples
Course 2
1-1
Populations and Samples
Learn to identify populations and random samples.

5. Populations and Samples
Course 2
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Populations and Samples
Vocabulary
population
sample
random sample

6. Populations and Samples
Course 2
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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.

7. Populations and Samples
Course 2
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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.

8. Populations and Samples
Course 2
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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

9. Populations and Samples
Course 2
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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

10. Populations and Samples
Course 2
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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

11. Populations and Samples
Course 2
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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
Sample
All seventh graders
50 students who are surveyed

12. Populations and Samples
Course 2
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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

13. Populations and Samples
Course 2
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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

14. Populations and Samples
Course 2
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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.

15. Populations and Samples
Course 2
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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.

16. Populations and Samples
Course 2
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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.

17. Populations and Samples
Course 2
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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.

18. Populations and Samples
Course 2
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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.

19. Populations and Samples
Course 2
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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.

20. Populations and Samples
Course 2
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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.

21. Populations and Samples
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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.
B. Identify the population.
people who bought TVs in the last month
all residents of Orlando

22. Populations and Samples
Course 2
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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.
B. The newspaper surveys every twentieth student entering the school.
No; only seniors are being surveyed.
No; not every student entering the school has a chance to be chosen.