Lesson 2

Both linear regression equations and lines of best fit can be used to make predictions based on a set of data. In Try This 3, you will explore how multiple sets of data can be used to solve a problem.

Try This 3

Jean and Mohammad were discussing health issues and what blood pressure tells you. Jean said that systolic blood pressure is affected by age, and Mohammad said he believed it was related more closely to weight. They obtained the following data for ten patients.

You want to test both Jean’s and Mohammad’s hypotheses.

1.  
   1. Consider Jean’s hypothesis. Which variable is dependent, and which is independent? Explain your reasoning.
   2. Create a scatter plot for Jean’s hypothesis.
2.  
   1. State which variable is independent and which is dependent for Mohammad’s hypothesis.
   2. Create a scatter plot for Mohammad’s hypothesis.
3. Explain whose hypothesis is more likely to be correct by referring to the scatter plots.
4.  
   1. Explain why it is reasonable to use a line of best fit for both graphs. For what kind of scatter plot is it unreasonable to use a line of best fit?
   2. Determine the equation of a line of best fit for both scatter plots.
5. What would be the expected systolic blood pressure for an 80 year old?
6. What would be the expected blood pressure for a person weighing 300 lb?

Save your responses in your course folder.

Share 2

With a partner or in a group, discuss answers for the following questions.

1. Did you agree about who had the correct hypothesis? If not, explain why.
2. Were your equations of the lines of best fit the same? Explain why or why not.
3. What would be an appropriate domain and range for each of your lines of best fit?

If required, place a summary of your discussion in your course folder.