Standardizing Variables in SAS Using PROC STDIZE

Standardizing Variables in SAS Using PROC STDIZE, Standardizing a variable involves scaling its values so that the mean is 0 and the standard deviation is 1.

This process is particularly useful in data analysis when you want to ensure that different variables contribute equally to the analysis.

Standardizing Variables in SAS Using PROC STDIZE

To standardize a variable, you can use the formula:

(x_i – x) / s

where:

• x_i: The i^th value in the dataset
• x: The sample mean
• s: The sample standard deviation

In SAS, the simplest way to standardize variables is by using the PROC STDIZE statement. Below, we’ll walk through an example of how to apply this in practice using a dataset of basketball players.

Example: Using PROC STDIZE in SAS

Let’s create a dataset containing information about various basketball players:

/* Create the dataset */
data my_data;
    input player $ points assists rebounds;
    datalines;
A 18 3 15
B 20 3 14
C 19 4 14
D 14 5 10
E 14 4 8
F 15 7 14
G 20 8 13
H 28 7 9
I 30 6 5
J 0 31 9 4
;
run;

/* Display the dataset */
proc print data=my_data;
run;

After creating the dataset, we can utilize the PROC STDIZE statement to standardize all numeric variables within the dataset:

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/* Standardize all numeric variables in the dataset */
proc stdize data=my_data out=std_data;
run;

/* View the standardized dataset */
proc print data=std_data;
run;

In the resulting dataset (std_data), all numeric variables (points, assists, and rebounds) will be standardized, each now having a mean of 0 and a standard deviation of 1.

If you want to standardize only specific variables, you can use the VAR statement within PROC STDIZE. For instance, to standardize just the points variable, you would write:

/* Standardize only the points variable in the dataset */
proc stdize data=my_data out=std_data;
    var points;
run;

/* View the updated dataset */
proc print data=std_data;
run;

In this case, only the values in the points column are standardized, while other columns remain unchanged.

To confirm that the points variable has been standardized correctly to have a mean of 0 and a standard deviation of 1, we can use the PROC MEANS statement:

/* View the mean and standard deviation of each variable */
proc means data=std_data;
run;

By running this command, you will see that the points variable now exhibits a mean of 0 and a standard deviation of 1, confirming that the standardization process was successful.

Conclusion

Standardizing variables is an important step in data preprocessing, particularly when preparing for analyses that may be sensitive to the scale of the variables involved.

Using PROC STDIZE in SAS makes this process straightforward and efficient, allowing for enhanced data analysis and interpretation.

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