Computing Correlations Using Pearson Correlation Coefficients
 
  

 


Enter the data for the X variable into the webulator and click through the panels. Be sure to record the values as the numbers are not stored. Then, enter the data for the Y variable into the webulator and click through the panels. Be sure to record the values as the numbers are not stored.

In this example, consider the treadmill VO2 max scores to be the X variable and consider the 12 minute run VO2 scores to be the data for the Y variable.

Treadmill Scores: 47,36,55,39,57,46,43,29,54,37

12 Minute Run Scores: 33,19,25,41,27,39,36,31,28,44

Position of number in the dataset Input Column
01
02
03
04
05
06
07
08
09
10
N = 10 Sum =
(sum of scores) / N = mean =

Next click the button labelled "Difference scores", located at the bottom of the next form to compute the exact difference between each observed age that you entered, and the average age that was computed.

(raw score - mean score) mean =
difference score 1
difference score 2
difference score 3
difference score 4
difference score 5
difference score 6
difference score 7
difference score 8
difference score 9
difference score 10

Click Square Difference Scores
This will advance the calculation through to the computation

(difference scores)2
squared score 1
squared score 2
squared score 3
squared score 4
squared score 5
squared score 6
squared score 7
squared score 8
squared score 9
squared score 10


Print the following table (or copy it to your word processor) to record the output from the computations in the webulator above so that you can compute the correlation coefficient.

The mean for X is: _______________________

The mean for Y is: _______________________

Participant Number treadmill
VO2 max
ml/kg/min
X		 12 minute run
VO2 max
ml/kg/min
Y		 (xi- mean)
ΔX		 (yi- mean)
ΔY		 Cross Product
of
ΔX * ΔY		 (xi- mean)2 (yi- mean)2
01 47 33          
02 36 19          
03 55 25          
04 39 41          
05 57 27          
06 46 39          
07 43 36          
08 29 31          
09 54 28          
10 37 44          
          Σ(ΔX * ΔY)
 		 Σ(Xi - mean)2
 		 Σ(Yi - mean)2
 



The numerator is: Σ(ΔX * ΔY) : _______________________

The denominator is:  the square root of the product of Σ(Xi - mean)2 * Σ(Yi - mean)2 _______________________

Click here to return to the Webulator Menu Page
For more information, please contact:

Professor William J. Montelpare, Ph.D.,
Margaret and Wallace McCain Chair in Human Development and Health,
Department of Applied Human Sciences, Faculty of Science,
Health Sciences Building, University of Prince Edward Island,
550 Charlottetown, PE, Canada, C1A 4P3
(o) 902 620 5186


Visiting Professor, School of Healthcare, University of Leeds,
Leeds, UK, LS2 9JT
e-mail wmontelpare@upei.ca
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