6th Grade Math Textbook, Fundamentals

Lesson 8-1 for exercise sets. &KDSWHU 

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Choose the sample that is more likely to be representative of the population.

1.To survey teens about their music preferences, you would question several teens:

a. attending a classical choir recital. b. as they enter a music store.

2.Write and solve a proportion to predict the number of “No” votes in a voting

population of 500. Use the frequency table at the top of this page.

3.In a random sample of 60 shoppers, 12 said that they only buy products

that are on sale. If there are 3000 shoppers at the mall today, about how

many would you predict only buy items on sale?

4.Discuss and Write How would you sample the students in your school to

accurately find out the name of their favorite professional sports team?

Think



“Yes” votes in population

Size of population

“Yes” votes in sample

Size of sample

A shows the number of times each type of answer occurs.

To organize data in a frequency table:

List all the possible responses.

Use tally marks to record the data.

Count and record the tally marks (called the of each response).

Add the frequencies to keep a running total of the number of all the

responses (called the ).

This frequency table shows Alonzo’s findings after surveying 80 voters.

The frequency table shows that 48 of 80 people surveyed favor the Mayor’s plan.

Proportional reasoning can be used to make predictions for a population

if the data are based on carefully chosen samples.

How many “Yes” votes would you predict there

would be in a voting population of 4000?

Let nthe predicted number of “Yes” votes in a voting population of 4000.

 Write a proportion.

48 • 4000 80 • n Cross multiply.



n 2400

So you could predict that 2400 people in a voting population of 4000 would vote “Yes.”

frequency

frequency table

cumulative frequency

Question: Should bicycle lanes be placed on most streets?

Response Tally Frequency Cumulative Frequency

Ye s 5 5 5 5 5 5 5 5 5 3 48 48

No 5 5 5 5 20 68

No Opinion 5 5 2 12 80

Divide both sides by

80 to isolate n.

80 • n

80

192,000

80

n

4000

48

80