1. Correlation Coefficient Using Technology

2. Remember:
Correlation Coefficient= indicates how closely data points are to forming a straight line (shows the strength of correlation).
“r” represents the correlation coefficient
Only for scatter plots that appears to have a linear association
The value of the correlation coefficient is -1 ≤ r ≤ 1
+1 is perfect positive correlation, very strong (an actual line)
0 is no correlation
-1 is perfect negative correlation, very strong (an actual line with negative slope).

3. Perfect straight decreasing line
Perfect straight increasing line

4. Enter the data into a graphing calculator.
Forearm Length (cm)
Foot Length (cm) 22 24 20 19 21 23 25 18 27
r can be calculated by a formula, using a graphing calculator, or an Excel spreadsheet.
Example: How strong of a relationship is there between the length of your forearm and the length of your foot in centimeters?
Enter the data into a graphing calculator.

5. How do you calculate r with a graphing calculator?

7. How do you calculate r in Excel or a Google Sheet?
r can be calculated by a formula, using a graphing calculator, or an Excel spreadsheet.
Step 1: Enter data into two columns on the spreadsheet.
Step 2: Highlight or click on the box where you want the correlation coefficient displayed.
Step 3: In Google Sheets type in the formula
=CORREL(A____:A____, B____:B______)
Click enter.
Reformat your correlation coefficient to the number of decimal places you desire.
Where your data starts in the first column.
Where your data starts in the second column.
Where your data ends in the first column.
Where your data ends in the second column.

8. Google Sheet The correlation coefficient is calculated.
Type in formula with correct cell ranges.
Reduce the number of decimal places.
Is this a strong, moderate or weak correlation?