Holt CA Course 1

7-4 Analyzing Data Displays

SDAP2.5 Identify claims based on statistical data and, in simple cases, evaluate the validity of the claims.Also covered: SDAP2.3

California Standards

Holt CA Course 1

7-4 Analyzing Data Displays

Vocabulary

bar graphcircle graphsectorline graph

Holt CA Course 1

7-4 Analyzing Data Displays

Graphs are often used to display and compare data. They can present a large amount of information in a way that is easy to understand.

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Electoral Votes Cast

RepublicansDemocrats2000 2004

Holt CA Course 1

7-4 Analyzing Data Displays

A bar graph uses vertical or horizontal bars to display data. This graph is a double-bar graph. It shows two related sets of data. The blue bars represent the number of electoral votes cast by Democrats, and the red bars represent the number of electoral votes cast by Republicans.

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19961988 1992

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Electoral Votes Cast

RepublicansDemocrats2000 2004

Holt CA Course 1

7-4 Analyzing Data Displays

Use the bar graph in the previous slide to answer the question.

Additional Example 1: Analyzing a Bar Graph

A. In which year did Democrats cast the fewest number of electoral votes?

The bar for 1988 is the shortest, so Democrats cast the fewest number of electoral votes in 1988.

Holt CA Course 1

7-4 Analyzing Data Displays

Use the bar graph to answer the question.

Additional Example 1: Analyzing a Bar Graph

B. Marco claims that Republicans cast about twice as many electoral votes in 2004 as they did in 1996. Is his claim valid? Explain.

Yes. They cast about 150 electoral votes in 1996 and almost 300 in 2004.

Holt CA Course 1

7-4 Analyzing Data Displays

Use the bar graph to answer the question.

Check It Out! Example 1

A. Which fruit was eaten the most?

The bar for bananas is the longest, so bananas were eaten the most.

Holt CA Course 1

7-4 Analyzing Data Displays

Use the bar graph to answer the question.

Check It Out! Example 1

B. About how many more pounds of apples than pounds of grapes were eaten per person?

About 10 pounds more apples were eaten than grapes per person.

Holt CA Course 1

7-4 Analyzing Data Displays

A circle graph, also called a pie chart, shows how a set of data is divided into parts.

The entire circle contains 100% of the data.

Each sector, or slice, represents one part of the data set.

The circle graph on the next slide shows the results of a survey about pet ownership. The graph makes it easy to see that half of the people surveyed have no pets.

Holt CA Course 1

7-4 Analyzing Data Displays

Leon surveyed 30 people about pet ownership. The circle graph shows his results. Use the graph to answer each question.

Additional Example 2: Analyzing a Circle Graph

A. How many people own both cats and dogs?

Since 20% is 6 people, 10% is 3 people.

3 people own both cats and dogs.

Holt CA Course 1

7-4 Analyzing Data Displays

Leon surveyed 30 people about pet ownership. The circle graph shows his results. Use the graph to answer each question.

Additional Example 2: Analyzing a Circle Graph

B. Maya claims that about 1/2 of the people surveyed do not own a cat. Is her claim valid? Explain.

No. The graph shows that 50% do not own pets and 20% own dogs only. In all, 70% do not own cats, and 70% > 1/2.

Holt CA Course 1

7-4 Analyzing Data DisplaysCheck It Out! Example 2

Fifty students were asked which instrument they could play. The circle graph shows the responses. Use the graph to answer each question.

A. How many students do not play an instrument?

Piano20%

No instrument50%

Flute10%

Drum20%

The circle graph shows that 50% of 50 students do not play an instrument.

50% of 50 = 0.5 • 50

= 25

25 students do not play an instrument.

Holt CA Course 1

7-4 Analyzing Data Displays

Check It Out! Example 2

B. Miles claims that 1/2 of the people surveyed play an instrument. Is his claim valid? Explain.

Yes; 20% of the people surveyed play the piano, 20% play the drum, and 10% play the flute. In all 50% or 1/2 play an instrument.

Piano20%

No instrument50%

Flute10%

Drum20%

Fifty students were asked which instrument they could play. The circle graph shows the responses. Use the graph to answer each question.

Holt CA Course 1

7-4 Analyzing Data Displays

In a line graph, data points on a coordinate grid are connected with line segments. Line graphs are often used to show how numerical data changes over time.

Holt CA Course 1

7-4 Analyzing Data Displays

Use the line graph to answer the question.

Additional Example 3: Analyzing a Line Graph

A. In approximately what year did Florida’s population first reach 5 million?

The graph shows that Florida’s population reached 5 million people in 1960.

Holt CA Course 1

7-4 Analyzing Data Displays

Use the line graph to answer the question.

Additional Example 3: Analyzing a Line Graph

B. Roy claims that Florida’s population more than tripled between 1960 and 2000. Is his claim valid? Explain.

Yes, the population in 1960 was about 5 million, and the population in 2000 was more than 15 million.

Holt CA Course 1

7-4 Analyzing Data Displays

Use the line graph to answer the question.

Check It Out! Example 3

A. What was the approximate population of Florida in 1970?

The graph shows about 7.5 million people.

Holt CA Course 1

7-4 Analyzing Data Displays

Use the line graph to answer the question.

Check It Out! Example 2

B. Tasha claims that Florida’s population doubled between 1960 and 2000. Is her claim valid? Explain.

No; the population in 1960 was 5 million and the population in 2000 was 15 million.