1. Warm Up/POD #5 Write the sentences. 1. What is the x-coordinate of the point (2, 3)? 2. To plot the point (3, 7) you would move right ___ units then up ___ units. 3. To plot the point (4, –5) would you move left or right first? 2 37 right

2. S CATTER PLOTS L EARN TO DISPLAY AND ANALYZE DATA IN SCATTER PLOTS. Agenda Warm-Up Notes Vocabulary Words Vocabulary 28. scatter plot 29. positive correlation 30. negative correlation 31. no correlation

3. 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. Scatter plots Notes

4. Use the data to make a scatter plot. Describe the relationship between the data sets. Example 1: Making a Scatter Plot 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

5. Example 1 Continued 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 Step 3: Label the axes and give the graph a title.

6. Example 2 Step 1: Determine the scale and interval for each axis. Place the year on the horizontal axis and the number of farm workers 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.

7. Example 2 Continued 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 Step 3: Label the axes and give the graph a title.

8. There are three ways to describe data displayed in a scatter plot. 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.

9. Write positive correlation, negative correlation, or no correlation to describe each relationship. Explain. 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 outdoor temperature and coat sales As the outdoor temperature increases, the number of coat sales will decrease. So there would be a negative correlation between the data sets. Example 3: Determining Relationships Between Two Sets of Data There would not be any correlation between these two variables. eye color and age

10. Lesson Quiz: Part I 1. Use the data to make a scatter plot. Describe the relationship. TemperatureAttendance 70 100 80 350 75 250 85 400 74 200 82 375 72 260 The graph shows a positive correlation.

11. Lesson Quiz: Part II 2. Write positive, negative, or no correlation to describe each relationship. Explain negative correlation; as age increases, attendance decreases.