http://www.ck12.org Chapter 7. Organizing and Displaying Data
The correlation coefficient will have a value between−1 and 1. The closer the correlation coefficient is to−1 or
1, the stronger the correlation. If the correlation coefficient is negative, this implies a negative correlation, and if
the correlation coefficient is positive, this implies a positive correlation. The coefficient of determination is just the
correlation coefficient squared, and, therefore, it is always positive. The closer the coefficient of determination is to
1, the stronger the correlation.
Example A
The following table consists of the marks achieved by 9 students on chemistry and math tests. Create a scatter plot
for the data with your calculator.
TABLE7.8:
Student A B C D E F G H I
Chemistry
Marks49 46 35 58 51 56 54 46 53
Math
Marks29 23 10 41 38 36 31 24?
Example B
Draw a line of best fit for the data that you plotted in Example A. Use the line of best fit to calculate the predicted
value for Student I’s math test mark.
The calculator can now be used to determine a linear regression equation for the given values. The equation can be
entered into the calculator, and the line will be plotted on the scatter plot.