1. 2.5 Using Linear Models A scatter plot is a graph that relates two sets of data by plotting the data as ordered pairs. You can use a scatter plot to determine the strength of the relationship, or correlation, between data sets. The closer the data points fall along a line, – The stronger the relationship and – The stronger the positive or negative correlation between the two variables.

2. Correlation

3. Using a Scatter Plot A trend line is a line that approximates the relationship between the variables, or data sets, of a scatter plot. The trend line can be used to make predictions from the data.

4. Trend Lines The trend line that gives the most accurate model of related data is the line of best fit. One method for finding a line of best fit is linear regression. You can use the LinReg function on your graphing calculator to find the line of best fit. The correlation coefficient, r, indicates the strength of the correlation. The closer r is to 1 or -1, the more closely the data resembles a line and the more accurate your model is likely to be.

5. Finding the Line of Best Fit See example 3 on p. 95.

6. More Practice!!!!! Homework – Textbook p. 96 #7 – 12.