**Preview** Warm Up California Standards Lesson Presentation

**Warm Up** Find percent of each number. 1. 40% of 300 2. 35% of 16 3. 23% of 80 Order the numbers from least to greatest. 4. 6.7, 6.2, 7.1 5. 8.9, 8, 9 6. 4.5, 4.05, 4.55 120 5.6 18.4 6.2, 6.7, 7.1 8, 8.9, 9 4.05, 4.5, 4.55

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

**Objective: You will learn how to (YWLHT) analyze data** displays and evaluate claims based on data displays.

**Vocabulary** bar graph circle graph sector line graph

**Electoral Votes Cast** 500 400 300 200 100 0 Number of Votes 2000 2004 1996 1988 1992 Democrats Republicans 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.

**Electoral Votes Cast** 500 400 300 200 100 0 Number of Votes 2000 2004 1996 1988 1992 Democrats Republicans 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.

**Example 1: Analyzing a Bar Graph** Use the bar graph in the previous slide to answer the question. 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.

**Example 2: Analyzing a Bar Graph** Use the bar graph to answer the question. 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.

**Check It Out! Example 3** Use the bar graph to answer the question. A. Which fruit was eaten the most? The bar for bananas is the longest, so bananas were eaten the most.

**Check It Out! Example 4** Use the bar graph to answer the question. 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.

**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. Eachsector, 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.

**Example 5: Analyzing a Circle Graph** Leon surveyed 30 people about pet ownership. The circle graph shows his results. Use the graph to answer each question. 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.

**Example 6: Analyzing a Circle Graph** Leon surveyed 30 people about pet ownership. The circle graph shows his results. Use the graph to answer each question. 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.

**Check It Out! Example 7** Fifty students were asked which instrument they could play. The circle graph shows the responses. Use the graph to answer each question. Flute 10% A. How many students do not play an instrument? Drum 20% The circle graph shows that 50% of 50 students do not play an instrument. 50% of 50 = 0.5 • 50 No instrument 50% Piano 20% = 25 25 students do not play an instrument.

**Check It Out! Example 8** Fifty students were asked which instrument they could play. The circle graph shows the responses. Use the graph to answer each question. Flute 10% Drum 20% 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. No instrument 50% Piano 20%

**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.

**Example 9: Analyzing a Line Graph** Use the line graph to answer the question. 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.

**Example 10: Analyzing a Line Graph** Use the line graph to answer the question. 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.

**Check It Out! Example 11** Use the line graph to answer the question. A. What was the approximate population of Florida in 1970? The graph shows about 7.5 million people.

**Check It Out! Example 12** Use the line graph to answer the question. 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.

**Home Learning** Click to view Lesson Videos

**Lesson Quiz: Part I** Use the bar graph for Exercises 1 and 2 to answer each question. 1. What was the approximate maximum 24-hour precipitation for Virginia? 2. Emma claims that the maximum 24-hour precipitation for Florida is about 27 inches more than for Indiana. Is her claim valid? Explain. about 27 in. yes

**Lesson Quiz: Part II** Use the circle graph for Exercises 3 and 4 to answer each question. 3. In 2005, what percent of overseas visitors came from Europe or Asia? 4. Jay claims that in 2005 less than 1/4 of overseas visitors came from Asia. Is his claim valid? 77% no

**Lesson Quiz: Part IIl** Use the line graph for Exercises 5 and 6 to answer each question. 5. What was the approximate average cost of a major league baseball ticket in 1995? 6. Kelsey claims that the average price of a major league baseball ticket increased by more than $10 between 1991 and 2005. Is her claim valid? about $11 yes