Data visualization with SAS programming

Box and Whisker Plots with p-value included

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Occasional Contributor
Posts: 7
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Box and Whisker Plots with p-value included

I am looking for a nice way to represent information on a given study for my classroom.  I have two separate groups A and B and want to compare them (hoping that B is statistically significantly better than A).  How can I program this?  I am very new to this and not sure what to do!  I think a box an whisker plot would look nice, but also want the p-value shown on the top comparing the two.

A 2.7

A 0.0

A 3.1

A 4.6

B 6.2

B 5.2

B 3.5

B 3.6

B 5.9

Any help is appreciated!  Thank you Smiley Happy


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‎08-14-2014 01:15 PM
SAS Employee
Posts: 5

Re: Box and Whisker Plots with p-value included

The SAS code below takes your data set and reads the A and B into a variable called GROUP and the measures into a variable called VALUE.  I then ran the TTEST procedure with plots=box.  The output shows the p-values in a table and the boxplot below if that is okay.  This is one of the easiest ways I could think of.  The SAS output is contained in the attached pdf file.  All the best - Randy

data work.compare;

length group $1;
input group value;
cards;

A 2.7

A 0.0

A 3.1

A 4.6

B 6.2

B 5.2

B 3.5

B 3.6

B 5.9

;
run;
ods graphics on;


proc ttest data=work.compare plots=box;
class group;

var value;
ods graphics off;

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Grand Advisor
Posts: 9,713

Re: Box and Whisker Plots with p-value included

You will need to run a test that creates p-values. Depending on the version of SAS you are using then you can add that value to a graph using an annotate dataset with your graph procedure.

Also, is that your actual data or do you have more records? Tests for a small sample is displayed are going to much different than for a larger sample. Also when compare (test) are you looking at means or distribution or something else?

Solution
‎08-14-2014 01:15 PM
SAS Employee
Posts: 5

Re: Box and Whisker Plots with p-value included

The SAS code below takes your data set and reads the A and B into a variable called GROUP and the measures into a variable called VALUE.  I then ran the TTEST procedure with plots=box.  The output shows the p-values in a table and the boxplot below if that is okay.  This is one of the easiest ways I could think of.  The SAS output is contained in the attached pdf file.  All the best - Randy

data work.compare;

length group $1;
input group value;
cards;

A 2.7

A 0.0

A 3.1

A 4.6

B 6.2

B 5.2

B 3.5

B 3.6

B 5.9

;
run;
ods graphics on;


proc ttest data=work.compare plots=box;
class group;

var value;
ods graphics off;

Occasional Contributor
Posts: 7

Re: Box and Whisker Plots with p-value included

Is there anyway on the box-plot that I could include all the data points?

Both your answer (RandyCollica) and (stat@sas) answers are exactly what I needed!!  Thank you Smiley Happy

Trusted Advisor
Posts: 1,192

Re: Box and Whisker Plots with p-value included

Check proc boxplot that allows to put stats on the box plot. I don't think it will allow to put all data points.

Trusted Advisor
Posts: 1,192

Re: Box and Whisker Plots with p-value included

Hi,

This can provide the boxplot with p value added on it.

ods graphics on;

ods select boxplot;

proc anova data=have;

class group;

model value=group;

quit;

ods graphics off;

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