1. 2.5 CORRELATION AND BEST-FITTING LINES

2. IN THIS LESSON YOU WILL : Use a scatter plot to identify the correlation shown by a set of data. Approximate the best-fitting line for a set of data.

3. SCATTER PLOT A scatter plot is a graph used to help determine whether there is a relationship between paired data. Sometimes scatter plots follow patterns that are approximately linear.

4. SCATTER PLOT In the scatter plot shown, y tends to increase as x increases. We say the paired data has a positive correlation.

5. SCATTER PLOT In the scatter plot shown, y tends to decrease as x increases. We say the paired data has a negative correlation.

6. SCATTER PLOT No Linear Pattern?? We say the paired data has a Relatively no correlation.

7. APPROXIMATING BEST-FITTING LINES FOR A SCATTER PLOT Sketch a line that appears to the pattern of the line. There should be as many points above the line are there are below the line. Pick two points on the line, and estimate the coordinates of each. These two points do not have to be original data points. (9,6) (-1,-4) Use the point-slope formula to find the equation of the line. y = x-3 This equation models the data