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Linear Regression and Correlation

Regression (Textbook Cost)

OpenStaxCollege

Regression (Textbook Cost)

Class Time:

Names:

Student Learning Outcomes
  • The student will calculate and construct the line of best fit between two variables.
  • The student will evaluate the relationship between two variables to determine if that relationship is significant.

Collect the Data
Survey ten textbooks. Collect bivariate data (number of pages in a textbook, the cost of the textbook).

  1. Complete the table.
    Number of pages Cost of textbook
  2. Which variable should be the dependent variable and which should be the independent
    variable? Why?
  3. Graph “pages” vs. “cost.” Plot the points on the graph in Analyze the Data. Label both axes with words. Scale both axes.

Analyze the Data
Enter your data into your calculator or computer.
Write the linear equation, rounding to four decimal places.

  1. Calculate the following:
    1. a = ______
    2. b = ______
    3. correlation = ______
    4. n = ______
    5. equation: y = ______
    6. Is the correlation significant? Why or why not? (Answer in complete sentences.)
  2. Supply an answer for the following senarios:
    1. For a textbook with 400 pages, predict the cost.
    2. For a textbook with 600 pages, predict the cost.
  3. Obtain the graph on your calculator or computer. Sketch the regression line.
    Blank graph with vertical and horizontal axes.
Discussion Questions
  1. Answer each question in complete sentences.
    1. Does the line seem to fit the data? Why?
    2. What does the correlation imply about the relationship between the number of pages and the cost?
  2. Are there any outliers? If so, which point(s) is an outlier?
  3. Should the outlier, if it exists, be removed? Why or why not?

License

Creative Commons License
Regression (Textbook Cost) by OpenStaxCollege is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.