0.14 Linear regression and correlation: regression lab ii (edited

Class Time:

Name:

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

• Complete the table.

  Number of pages	Cost of textbook

• Which variable should be the dependent variable and which should be the independent variable? Why?
• Graph “number of pages” vs. “cost.” Plot the points on the graph. Label both axes with words. Scale both axes.
  Does there appear to be a relationship between the size of the book and it's cost?

Analyze the data

Enter your data into your MiniTab. Record the following information.

• correlation coefficient = ___________
• p-value = ___________
• Is three significant correlation to use a regression line?

• Calculate the following:

  • A

    $a$ =

  • B

    $b$ =

  • C

    $n$ =

  • D

    equation: $y$ =
• Obtain the graph using Minitab. Sketch the regression line below.

• Supply an answer for the following senarios:

  • A

    For a textbook with 400 pages, predict the cost:

  • B

    For a textbook with 600 pages, predict the cost:

Discussion questions

• Answer each with 1-3 complete sentences.

  • A

    Does the line seem to fit the data? Why?

  • B

    What does the correlation imply about the relationship between the number of pages and the cost?
• Are there any outliers? If so, which point(s) is an outlier?
• Should the outlier, if it exists, be removed? Why or why not?