Example 3

Caitlyn thinks that there may be a relationship between class size and student performance on standardized tests. She recorded the number of students in 20 classes, along with the average test score in each class, in the following table. Is there a linear relationship between class size and average test score? Use the correlation coefficient, r, to explain your answer.
  1. Create a scatter plot of the data.
  2. Describe the relationship between the data using the graphical representation.
  3. Calculate the correlation coefficient on your graphing calculator.
  4. Use the correlation coefficient to describe the strength of the relationship between the data.
This applet is provided by Walch Education as supplemental material for their mathematics programs. Visit www.walch.com for more information on their resources.