The SAS **mean()** function allows you to find the mean value across columns and returns the average in a data step.

```
data example;
a = mean(1,4,7);
put a;
b = mean(1,.,-1);
put b;
run;
/* Log Output */
4
0
```

When working with different data in programming, the ability to be able to easily find summary statistics of pieces of your data is valuable.

One such case is if you want to find the average of multiple values.

In a SAS data step, you can find the mean of multiple numbers or multiple columns with the **mean()** function.

Below shows you some simple examples of using **mean()** in a SAS data step.

```
data example;
a = avg(1,4,7);
put a;
b = avg(1,.,-1);
put b;
run;
/* Log Output */
4
0
```

## Find Average Across Columns in Data Step with mean()

You can use **mean()** to create a new column which has the mean value across a number of columns in a SAS dataset.

For example, let’s say you had some variables and wanted to find the mean for each observation of those variables.

To do this, you can use **mean()** and pass the column names as the arguments.

Below shows you how to create a new column which is the mean value across the columns A, B and C in a data step.

```
data example;
input A B C;
datalines;
5 1 2
4 2 3
3 3 4
2 4 5
1 5 6
;
run;
data example_with_average;
set example;
M = mean(A,B,C);
run;
/* Output */
A B C M
5 1 2 2.666666667
4 2 3 3
3 3 4 3.333333333
2 4 5 3.666666667
1 5 6 4
```

## Treatment of Missing Values with SAS mean() Function in Data Steps

If your data has missing values, then you have to be aware of how **mean()** calculates the average if you have values which are missing that are passed to **mean()**.

In general, missing values will be ignored by **mean()**.

This is shown below, where I’ve included one missing value in the call to **mean()**.

```
data example;
a = mean(1,.,-1);
put a;
run;
/* Log Output */
0
```

However, if all values are missing, then **mean()** will return a missing value.

```
data example;
a = mean(.,.,.);
put a;
run;
/* Log Output */
.
```

## Find Average of Entire Column in SAS with PROC MEANS

If you want to find the average of an entire column, then you should use PROC MEANS.

In SAS, PROC MEANS is a procedure which allows you to create summaries of your data and allows you to calculate things like the average, mean, average, average, etc. of a variable.

You can find the mean of an entire column by specifying the MIN option with PROC MEANS.

Below shows you how to find the mean of an entire column using the SAS PROC MEANS procedure.

```
data example;
input group $ value;
datalines;
A 1
A 2
A 3
B 4
B 5
B 6
C 7
C 8
;
run;
proc means data=example mean;
variable value;
run;
```

Hopefully this article has been useful for you to learn how to use the SAS **mean()** function in your SAS programs.

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