Introduction

Introduction

Stats Lab 12.2

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 whether that relationship is significant.

Collect the Data Survey 10 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
       
       
       
       
       
       
       
       
    Table 12.13
  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 a 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 scenarios:
    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 a calculator or computer. Sketch the regression line.
    Blank graph with vertical and horizontal axes.
    Figure 12.22
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 is an outlier?
  3. Should the outlier, if it exists, be removed? Why or why not?