Draw five columns on your paper labeled X, X-Squared, Y, Y-Squared, and X*Y. Fill in the data of your two variables in the two columns labeled X and Y.
Add up all the values of your X data and put this number at the bottom of the X column.
Add up all the values of your Y data and put this number at the bottom of the Y column.
Square each individual x data point, and put these numbers in the X-Squared column. Add these numbers all up and put this number at the bottom of the X-Squared column.
Square each individual Y data point, and put these numbers in the Y-Squared column. Add these numbers all up and put this number at the bottom of the Y-Squared column.
Multiple each X with its corresponding Y, and put these numbers in the the X*Y column. Add these numbers all up and put this number at the bottom of the X*Y column.
Count the number of data pairs you have, and write this number as "n= #."
Multiply the sum of X and the sum of Y, then divide by N. Take this number and subtract it from the sum of X*Y.
Square the sum of X and divide it by N. Subtract this from the sum of X squared.
Square the sum of Y and divide it by N. Subtract this from the sum of Y squared.
Multiply the results of steps 9 and 10, then find the square root.
Divide the number from step 8 by the number from step 11. That is your correlation coefficient. Write it as "r= #."