CURRICULUM WRITING PROJECT Program: Bio Tech Unit: Lesson Title: Linear Regression Duration: 2 days (?) Course: Course #: Lesson _____ of _____ Written by: Kathy English STANDARD & MEASUREMENT CRITERIA BIOSCIENCE, 41.0100.0 STANDARD 3.0 – DEMONSTRATE CRITICAL THINKING AND SCIENTIFIC PROBLEMSOLVING SKILL IN SCIENTIFIC INQUIRY 3.6 Collect, record, and analyze appropriate data Common Core State Standards – Math • HS.S-ID.6. Represent data on two quantitative variables on a scatter plot, and describe how the variables are related. a) Fit a function to the data; use functions fitted to data to solve problems in the context of the data. c) Fit a linear function for a scatter plot that suggests a linear association. • HS.S-ID.7. Interpret the slope (rate of change) and the intercept (constant term) of a linear model in the context of the data. OBJECTIVES MPS OBJECTIVE Written in student-friendly terms to post Students will be able to apply a linear regression formula to paired data to find the equation of the trend line and use the equation to predict values. Topic: Do: Find the line of best fit Level of thinking: Applying TERMINOLOGY – Must include up to six key terms or concepts with definitions Linear Regression – a line of best fit, found by using a mathematical algorithm, which describes the linear trend of two-variable data. INTRODUCTION (First Slide) Use as a bell-work or warm up: Think of a time when you made a prediction based on events that had already happened. What was the risk involved? How sure were you? How do you think analysts make their predictions about things like gas prices, the stock market, or Black Friday sales? [This may be too “Marketing-like” adjust as necessary.] 1 MPS CTE: LESSON PLAN Updated 4/4/12 TEACHER ACTIONS CONTENT STUDENT ACTIONS (Objectives reflected here) Call on a non-volunteer to hear responses for the introduction. After the first student has had a chance to give their answer, let him/her call on the next non-volunteer. 3 or 4 will probably be all you will have time for. Briefly discuss the terms on “Collecting Data.” Bi-variate data simply means values for two variables, usually an x and y. Show slide “Visual Aid” and ask students to guess a scenario to go with the graph. After being called on to give a response to the introduction, choose the next person to respond. Slide “So…What do You KNOW?” is an assessment of pre-requisite math. Give students a chance to do the problems individually, and then compare with an elbow partner. Hopefully, these examples will be super easy, but if a student feels as if they never ‘got’ this before, they need to brush up before they try the rest of this lesson. There are two slides titled “y = mx + b” and the next one is “Coincidence…” These slides reinforce the slide for assessing the math skills. Hopefully students will remember better after seeing these. Take the time to go over the next 4 slides, “Linear Function,” “Linear Regression…by hand,” “Fitting a line to data,” and “Interesting Fact” step by step because there are symbols and ideas that are most likely new to the students. “Make a table” slide is crucial to the mathematical success of the lesson! Remind the students that ‘x bar’ and ‘y bar’ means the average values. Unless students know (or remember) the basics of writing an equation of a line, this lesson may be really hard. Work these 5 problems alone, and then when your teacher says to, compare with your elbow partner. “Try an example…” sets up the table with data. Step through the information so that students can follow along on the notes. Students need a moment to calculate the means. “X-bar” and “Y-bar” are the first 2 MPS CTE: LESSON PLAN Students look at “visual aid” slide. They may confer with a partner to try to imagine a real-life situation that might be represented by the scattered data and the line. If that is difficult, perhaps try to guess the equation of the line. See note with the slide. Using the note-taker, fill in the blanks. Write questions that you need answered. Talk to an elbow partner to make sure both of you understands the concepts up to this point. Ask questions as needed. On the note-taker, students need to write in their own words what values are represented in each column, and examine the slope value formula. Be sure to write down the formula for slope and that you understand every part of it. You will not be expected to memorize this formula! Students will plot the points on the graph provided on the note-taker. Calculate the average x and average y. Fill in the first row of values as the teacher explains and check the answers. Updated 4/4/12 values to find. Next, have students calculate the first value in the (x – x-bar) column. X-bar is the same all the way down, but X changes on each row. Next, skip over to the column where you square that answer. Square it while it is in the calculator, it will just save time. Let students fill in those two columns, then click (each value will fly in on a click) through the answers to be sure everyone is on the right track. Next do the same thing with (y – y-bar) and square. Click to check the first value in those columns. But don’t show answers until students have tried to do it on their own. “Here’s where it all comes together…” is where the ‘big’ calculations come in! Have students find the slope using the formula and click to fly in the answer when everyone is ready. Next, have the students fill in the values to write the equation of the line. This is not difficult math, especially if you have a calculator to help! But…keep in mind that it takes time! Continue filling in the calculated values. Check answers with the teacher and make corrections if necessary. Don’t just copy if you don’t get it! Ask for help from an elbow-partner or the teacher. Sum the green column and the next-to-last column. These are the answers you need for the slope. “Extrapolate values…” Once the linear model has been established, the equation can be used to estimate ‘missing’ values, ones between the ones we were given originally. If you wanted to find the y-value that might have belonged with a given x-value, simply substitute in the known x and solve for y. If you wish to know where, along the x-axis, a certain y-value is likely to have occurred, the solving is just a little more involved, but not much harder to do. “Predict values…” Use the linear model to go beyond the given data. What happens beyond the known is tricky and mysterious. Caution should be used and you should always consider the actual experiment parameters when ‘predicting’ the future. As far as the algebra is concerned, using the equation is simple math! Students need to understand that if there is not a linear ‘trend’ to the data, then this method will not work. Students have to get to work here! Any time you have a point and a slope, you can write the equation of the line. Use the slope-intercept formula and fill in the values that you know. You know the ‘m’ and you know an (x, y) point. Substitute in to solve for ‘b’ the y-intercept. Examples on the notes-sheet are provided for extra practice. Examples on the notes-sheet are provided for extra practice. CLOSURE 1. What role does algebra play in analyzing this type of data? 2. Compare the level of accuracy obtained in using the algebra to what could be done by just estimating a trend line. 3. Think about the time it took to do the calculations for 5 data points. What would a 3 MPS CTE: LESSON PLAN Updated 4/4/12 business analyst do with hundreds of data points? FORMATIVE ASSESSMENT CONNECTIONS Typically in Algebra II, there is not enough time to go through the steps of the linear regression algorithm (although this may not be universally true). Math students are often asked to estimate the line of best fit…with no explanation of what makes it the best. It isn’t always portrayed as something that has application beyond the math classroom. The formulas are not essential to memorize because the technology available makes hand calculations unnecessary. SAMPLE END OF PROGRAM ASSESSMENT QUESTIONS Must be two or three multiple choice questions with answers highlighted. EQUIPMENT RESOURCES MATERIALS SUPPLIES (Everything that needs to be prepared and available in order to teach this lesson) ACCOMMODATIONS Citations from web sites referenced: ATTACHMENTS / HANDOUTS / POWER POINT Power Point Notes Sheet 4 MPS CTE: LESSON PLAN Updated 4/4/12