1. Warm-Up Exercises EXAMPLE 1 Describe the correlation of data Describe the correlation of the data graphed in the scatter plot. a. The scatter plot shows a positive correlation between hours of studying and test scores. This means that as the hours of studying increased, the test scores tended to increase. a.

2. Warm-Up Exercises EXAMPLE 1 Describe the correlation of data b. The scatter plot shows a negative correlation between hours of television watched and test scores. that as the hours of television This means that as the hours of television watched increased, the test scores tended to decrease. b.

3. Warm-Up Exercises GUIDED PRACTICE for Example 2 Make a scatter plot of the data in the table. Describe the correlation of the data. 2. ANSWER The scatter plot shows a positive correlation.

4. Warm-Up Exercises Daily Homework Quiz 1. Tell whether x and y show a positive correlation, a negative correlation, or relatively no correlation. ANSWER negative correlation.

5. Warm-Up Exercises BIRD POPULATIONS EXAMPLE 3 Write an equation to model data The table shows the number of active red-cockaded woodpecker clusters in a part of the De Soto National Forest in Mississippi. Write an equation that models the number of active clusters as a function of the number of years since 1990. Year 199219931994199519961997199819992000 Active clusters 222427 3440424551

6. Warm-Up Exercises STEP 1 SOLUTION EXAMPLE 3 Write an equation to model data Make a scatter plot of the data. Let x represent the number of years since 1990. Let y represent the number of active clusters.

7. Warm-Up Exercises STEP 3 EXAMPLE 3 Write an equation to model data STEP 4 STEP 2 Decide whether the data can be modeled by a line. Because the scatter plot shows a positive correlation, you can fit a line to the data. Draw a line that appears to fit the points in the scatter plot closely. Write an equation using two points on the line. Use (2, 20) and (8, 42).