1. Warm-up 3.2 Getting a line on the pattern Suppose you were to collect data for each pair of variables. You want to make a scatterplot. Which variable would you use as the explanatory variable, and which as the response variable? Write trend AND strength and your explanation. a)Scuba diving: depth, water pressure. b)All elementary school students: weight, reading level c) Lightning strikes: distance from lightning, time delay of thunder.

2. Student of the day! Block 1

3. Student of the day! Block 2

4. Discuss E #1-4 of 3.1

5. 3.2 Getting a line on the pattern Slope: ____ y-intercept = ____ How thick is 300 pages? Extrapolation, intrapolation…

6. Using the calculator to get the Regression Line or LSRL Actual- expected L 1 L 2 Y1(50) = Y1(250) = Residual

7. Finding Residuals using the calculator no need for “ “ L 3 = Y 1 (L1) subs. x values L 4 = L 2 -L 3 calculates residuals L 5 = L 4 2 squares them To predict 300 pgs Type Y1(300) ENTER

8. How to see the residual plot on the calculator! If the regression line is a good model, we would expect to find the residuals more or less randomly scattered about the average residual which is represented by the horizontal line. No pattern on the residual plot is a good thing.

10. Common test mistakes On free-response, when comparing values that are normally distributed, use z-score or percentile. Be sure to explain what they mean and why one is superior to the other. In general, numbers can not be given without explanation and explanation can not be given without specific numbers. Do no use calculator talk unless you explain in words. When only given the 5 number summary you can only determine if there are any outliers present. It can be more than one.

11. Advice for next test If you did poorly on the multiple choice, get a study guide (Barron’s or 5 steps to a 5) to do more practice multiple choice in time for the next test. If you did poorly on the free response, work on more problems beyond what is assigned for homework. Check out the college board website, I use released free- response from old exams and I use h.w. problems from other textbooks for free –response as well.

12. Common Test mistakes Homework: - 3.2 Copy the properties of the Least Squares Regression Line on pg 125; P #3 and 4, E # 9 and 10; Read 3.3

13. Answers to 3.1 Homework A.P. Statistics E #1-4

14. 3.1 E#2

15. A.P. Statistics H.W. Answers continued… E3. a. II b. IV c. III d. I E4.