11: Calculating the Pearson Correlation Coefficient with Excel
We start by
entering the
data of the
exams scores of
the 10 first‐year
psychology
students (Book p
283). The first
column shows
the scores on
the Stats exam;
the second
those of the
Social
Psychology
exam.
Although it is tempting to build the complete auxiliary table with the various equations (please, feel free to do so!), we’ll
limit ourselves to the built‐in function to calculate Pearson product‐moment correlations.
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Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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Activate Cell E1
(or whichever
cell in which you
want to have
your
correlation).
Click on fx to
open the
function panel of
Excel:
Select the
function CORREL
from the
Statistical
functions. Click
on OK.
Marc Brysbaert www.palgrave.com/psychology/brysbaert
Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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Enter A1:A10 in
the first entry
box and B1:B10
in the second
(tip: you can
easily do this by
putting your
cursor in the
entry box and
then going with
the mouse over
the cells while
keeping the left
key pressed).
Then click OK.
This gives you
the correlation
value of .4508
(check with the
solution on p.
284 of the book)
To calculate the intercept and the regression weight of the regression line, we can again make use of the formulas
described in the book or make use of the built‐in Excel functions. We demonstrate the latter (please, feel free to make your
own file with all the relevant information!).
Select the
function
INTERCEPT from
the Statistical
library.
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Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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Enter B1:B10 in
the box asking
for known_y’s
(the values that
have to be
predicted) and
A1:A10 in the
box asking for
known_x’s (the
values that are
used as
predictors).
Then click on OK
This gives you
the value of the
intercept:
Marc Brysbaert www.palgrave.com/psychology/brysbaert
Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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To find the value
of the slope of
the regression
line, use the
function SLOPE
This gives you
the required
value (cf. p 284):
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Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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In addition, we
may want to
have a scatter
plot of the data.
For this, go with
the cursor to Cell
E7 (or so) and
click on Insert
and Scatter:
Choose the
scatter plot:
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Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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Click on Select
Data.
Activate all
numbers both in
column A and B
by going over
them with the
mouse (left
button pressed
in). Start in Cell
A1 and go to Cell
B10. Then click
on OK:
Marc Brysbaert www.palgrave.com/psychology/brysbaert
Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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This gives you
the desired plot,
even though the
values on the
axis may not be
optimal:
To change this
activate the axis
you want to
change by left
clicking on it.
Then click on the
right mouse
button to see
the following
panel:
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Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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Select Format
Axis and adjust
the minimum
and maximum
value to desired
values:
Then do the
same for the Y‐
axis:
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Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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Which will give
you the
following
picture, in which
you can then
add axis labels,
titles, etc…
You can also try
out different
Chart Layouts.
To add the
regression line,
activate the dots
of the scatter
plot by clicking
on one of them.
Then click on the
right mouse
button to get
the following
panel, from
which you select
Add Trendline.
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Basic Statistics for Psychologists 11: Calculating the Pearson Correlation Coefficient with Excel
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