1. 1-8 Scatter Plots Course 2 Warm Up Warm Up Problem of the Day Problem of the Day Lesson Presentation Lesson Presentation

2. Warm Up Which of the following pairs do you think have a cause-and-effect relationship? 1. height and age 2. hand span and address 3. grade average and shoe size 4. temperature and date Course 2 1-8 Scatter Plots yes no yes

3. Problem of the Day From the pizza shop, James walks 12 blocks south, 22 blocks east, 18 blocks north, and 30 blocks west. James realizes that he left his wallet at the pizza shop. What is the least number of blocks James must walk to return to the pizza shop? Course 2 1-8 Scatter Plots 14 blocks

4. Learn to display and analyze data in scatter plots. Course 2 1-8 Scatter Plots

5. Vocabulary scatter plot positive correlation negative correlation no correlation Course 2 1-8 Scatter Plots

6. To find out if two sets of data may be related, you can make a scatter plot of the data values in each set. A scatter plot has two number lines, called axes—one for each set of data values. Each point on the scatter plot represents a pair of data values. These points may appear to be scattered or may cluster in the shape of a line or a curve. Course 2 1-8 Scatter Plots

7. Use the data to make a scatter plot. Describe the relationship between the data sets. Additional Example 1: Making a Scatter Plot Course 2 1-8 Scatter Plots Type U.S. Only Rest of World Mammals 63 251 Birds 78 175 Reptiles 14 64 Amphibians 10 8 Fishes 70 11 Clams 61 2 Number of Endangered Species Step 1: Determine the scale and interval for each axis. Place the number of animals endangered in the U.S. on the horizontal axis and the number of animals endangered in the rest of the world on the vertical axis. 0 20 40 60 80 300 240 180 120 60 0

8. Additional Example 1 Continued Course 2 1-8 Scatter Plots Type U.S. Only Rest of World Mammals 63 251 Birds 78 175 Reptiles 14 64 Amphibians 10 8 Fishes 70 11 Clams 61 2 Number of Endangered Species Step 2: Plot a point for each pair of values. 0 20 40 60 80 300 240 180 120 60 0

9. Use the data to make a scatter plot. Describe the relationship between the data sets. Additional Example 1 Continued Course 2 1-8 Scatter Plots Type U.S. Only Rest of World Mammals 63 251 Birds 78 175 Reptiles 14 64 Amphibians 10 8 Fishes 70 11 Clams 61 2 Number of Endangered Species Step 3: Label the axes and give the graph a title. 0 20 40 60 80 300 240 180 120 60 0 U.S. Rest of World Number of Endangered Species

10. Use the data to make a scatter plot. Describe the relationship between the data sets. Additional Example 1 Continued Course 2 1-8 Scatter Plots Type U.S. Only Rest of World Mammals 63 251 Birds 78 175 Reptiles 14 64 Amphibians 10 8 Fishes 70 11 Clams 61 2 Number of Endangered Species There appears to be no relationship between the data sets. 0 20 40 60 80 300 240 180 120 60 0 U.S. Rest of World Number of Endangered Species

11. Try This: Example 1 Course 2 1-8 Scatter Plots Step 1: Determine the scale and interval for each axis. Place the year on the horizontal axis and the cost on the vertical axis. 1940 1960 1980 2000 10,000 8,000 6,000 4,000 2,000 1940 8,995 1950 6,858 1960 4,132 1970 2,881 1980 2,818 1990 2,864 Number of farm workers in thousands Year Use the data to make a scatter plot. Describe the relationship between the data sets.

12. Try This: Example 1 Continued Course 2 1-8 Scatter Plots Step 2: Plot a point from each pair of values. 1940 8,995 1950 6,858 1960 4,132 1970 2,881 1980 2,818 1990 2,864 Number of farm workers in thousands Year 1940 1960 1980 2000 10,000 8,000 6,000 4,000 2,000

13. Try This: Example 1 Continued Course 2 1-8 Scatter Plots Step 3: Label the axes and give the graph a title. Year Number (in thousands) Number of Farm Workers 1940 8,995 1950 6,858 1960 4,132 1970 2,881 1980 2,818 1990 2,864 Number of farm workers in thousands Year 1940 1960 1980 2000 10,000 8,000 6,000 4,000 2,000

14. Try This: Example 1 Continued Course 2 1-8 Scatter Plots The number of farm workers decreased from 1940 to 1970. 1940 8,995 1950 6,858 1960 4,132 1970 2,881 1980 2,818 1990 2,864 Number of farm workers in thousands Year Number (in thousands) Number of Farm Workers 1940 1960 1980 2000 10,000 8,000 6,000 4,000 2,000

15. There are three ways to describe data displayed in a scatter plot. Course 2 1-8 Scatter Plots Positive Correlation The values in both data sets increase at the same time. Negative Correlation The values in one data set increase as the values in the other set decrease. No Correlation The values in both data sets show no pattern.

16. Write positive correlation, negative correlation, or no correlation to describe each relationship. Additional Example 2A: Determining Relationships Between Two Variables Course 2 1-8 Scatter Plots The graph shows that as area increases, population increases. So the graph shows a positive correlation between the data sets.

17. Write positive correlation, negative correlation, or no correlation to describe each relationship. Additional Example 2B: Determining Relationships Between Two Variables Course 2 1-8 Scatter Plots The graph shows that as the year increases, sales decrease. So the graph shows a negative correlation between the data sets.

18. Write positive correlation, negative correlation, or no correlation to describe each relationship. Additional Example 2C: Determining Relationships Between Two Variables Course 2 1-8 Scatter Plots The number of vacation days is not related to height. So there would not be any correlation between these two variables. height and number of vacation days

19. Write positive correlation, negative correlation, or no correlation to describe each relationship. Try This: Example 2A Course 2 1-8 Scatter Plots The graph shows that as the year increases, number of tornados increases. So the graph shows a positive correlation between the data sets.

20. Write positive correlation, negative correlation, or no correlation to describe each relationship. Try This: Example 2B Course 2 1-8 Scatter Plots The graph shows that as the length of string increases, frequency decreases. So the graph shows a negative correlation between the data sets. vps = vibrations per second

21. Write positive correlation, negative correlation, or no correlation to describe each relationship. Try This: Example 2C Course 2 1-8 Scatter Plots There would not be any correlation between these two variables. eye color and age

22. Lesson Quiz: Part 1 1. The table shows the daily attendance at the beach. Use the data to make a scatter plot of the data and describe the relationship between the data sets. Course 2 1-8 Scatter Plots TemperatureAttendance 70 100 80 350 75 250 85 400 74 200 82 375 72 260 The graph shows a positive correlation.

23. Lesson Quiz: Part 2 2. Write positive, negative, or no correlation to describe the relationship shown. Course 2 1-8 Scatter Plots negative correlation