1. 2.5 Using Linear Models P92-95

2. Scatter Plot: graph that relates 2 sets of data by plotting the ordered pairs. Correlation: strength of the relationship between data sets

4. Ex 1) Make scatter plot. Describe correlation.

5. Trend line: a line that approximates the relationship between the points on a scatter plot. HOW?? Find 2 points. Find slope. Write point-slope equation. Change to desired form.

6. Line of best fit: most accurate trend line. Lin Reg (Linear Regression) : function on graphing calculator that determines the equation of the line of best fit. Correlation coefficient (r): indicates the Strength of the correlation. The closer r is to 1 or -1, the more accurate the line of best fit is.

7. Ex 3) Find the equation for the line of best fit. How accurate is it? Let 1998 = year 1

8. Press STAT From EDIT menu, select 1: Edit. Clear data (highlight L1, press clear, press down arrow. Repeat for L2) Enter x coordinates in L1 Enter y coordinates in L2

10. Find equation: Press STAT From CALC menu, select 4: LinReg (ax+b) If r does not appear: press 2 nd Catalog, scroll to Diagnostics On, press enter twice

11. Round to 4 decimal places.

12. Based on the linear model, how much would you pay for a gallon of whole milk in 2020?

13. When would you expect milk to cost more than $5.00? Answer: Sometime in 2025