CCSS IP Math I 4.3.2 Example 3

Caitlyn thinks that there may be a relationship between class size and student performance on standardized tests. She tracks the average test performance of students from 20 different classes, and notes the number of students in each class in the table below. 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.
  4. Use the correlation coefficient to describe the strength of the relationship between the data.