30_SP_KeerthanaT

The principal at Marina Middle School wants to determine if the 120 students in the seventh grade prefer to visit Catalina Island or Camp Mosaic for their end-of-year trip. Which of the following is a representative sample of the population? Select all that apply.

• 20 sixth-grade students, 20 seventh-grade students, and 20 eighth-grade students

• 10 seventh-grade boys and 10 seventh-grade girls

• 25 seventh-grade students

• 15 seventh-grade boys and 5 teachers

• 25 students from the school

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CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

Starla polled the 2 customers who had been going to a particular barbershop the longest.  Is this sample of the customers likely to be representative?

• yes
• no

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CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

Andre wants to survey a random sample of the student body in his school to find out which day after school would work best for students to do volunteer work for a local charity. Which

sample would best represent the student body?

• asking twenty students waiting in line for lunch

• asking twenty students on their way to the bus after school

• asking one person from the seventh grade daily for twenty days

• asking one person each from twenty different classrooms during the first class period

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CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

A good sample must be: representative and random.

(Watch Mr. Jackson's video for help)

Which picture shows a representative sample?

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• 
• 
• 

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CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

A toy store owner wants to know how much kids spend each month on toys. Which choice is the best representation of the population?

• 220 wealthy kids

• All kids who buy toys

• 100 boys between ages 8 to 12

• 125 girls between ages 4 to 10

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CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

In order to use samples to estimate something from the population, the sample should be _________________ the population.

• exactly the same as
• nothing like
• representative of
• larger than

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CCSS.RI.7.7

CCSS.RI.8.7

CCSS.RL.6.7

CCSS.RL.7.7

CCSS.RL.8.7

There are 15 circles in the population.

20% of the circles are red.

The best representative sample would also have 20% red circles.

It is RARE for your sample to be EXACTLY the same. We hope the sample is SIMILAR or CLOSE.

In a sample of 3 each circle is 33% (so not 20%). Which sample is the MOST representative of the population?

Which is the BEST sample of the 4 random samples?

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• 
• 
• 

Answer explanation

The population is MOSTLY purple and SOME red.

This is the only sample that is MOSTLY purple and some red.

This is the MOST representative sample even though it is not exactly the same as the population.

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

BEWARE: Your sample does not allow for someone in China to be represented.

If you survey students in your town then your population is limited to students in your town.

What makes a sample representative?

• The sample is representative if it includes people from all over the world
• The sample is representative if it includes people from the same town
• The sample is representative if it includes people from the same country
• The sample is representative if it accurately reflects the group it is supposed to represent

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CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

What is a representative sample?

• A representative sample accurately reflects the characteristics of the whole population.

• A representative sample is a random selection of individuals from the population.

• A representative sample is a small subset of the population.

Answer explanation

A representative sample represents or is like the population.

Even if you have a random sample it might not be representative. We hope it is!

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

A cafeteria in a mall wants to conduct a survey on a new addition to the menu. Which of these samples would provide the MOST representative survey of its current customers?

• survey every 100th person who enters the mall

• survey every 10th person leaving the cafeteria

• survey every 5th child who enters the cafeteria

• survey every 50th woman leaving the mall

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CCSS.MATH.CONTENT.7.SP.A.2