1. Chapter 2 2.7 – Scatter Plots and Correlation

2. Scatter plot – graph of a set of data pairs (x, y) Correlation – relationship between the ordered pairs Positive Negative Relatively none

3. 2.7 – Scatter Plots and Correlation Positive Correlation As x increases, y tends to increase

4. 2.7 – Scatter Plots and Correlation Negative Correlation As x increases, y tends to decrease

5. 2.7 – Scatter Plots and Correlation Relatively no correlation There is no obvious pattern between x and y

6. 2.7 – Scatter Plots and Correlation Example 1 Describe the correlation shown.

7. 2.7 – Scatter Plots and Correlation Example 2 Describe the correlation shown

8. 2.7 – Scatter Plots and Correlation Best – fitting line – A line that most closely models a set of data

9. 2.7 – Scatter Plots and Correlation Steps for Approximating a best-fitting line Draw a scatter plot Sketch a line that follows the trend of the data. It should be close to as many points as possible. Choose 2 points that line on the line. Write an equation of the line that passes through the two points

10. 2.7 – Scatter Plots and Correlation Example 3 The table gives the systolic blood pressure y of patients x years old. Approximate the best- fitting line for data. X434856616770 y128120135143141152

11. 2.7 – Scatter Plots and Correlation Example 4 These data represent purchases at five gas stations in a city Gallons8.611.512.8 15.1 Cost ($)32.2544.2848.0048.7757.53

12. 2.7 – Scatter Plots and Correlation Example 4 (cont) Approximate the best-fitting line Predict the cost of 10.0 gallons of gas in the city Gallons8.611.512.8 15.1 Cost ($)32.2544.2848.0048.7757.53

13. 2.7 – Scatter Plots and Correlation HOMEWORK 2.7 Practice A Worksheet