You can use the following methods to calculate the mean of values by group in SAS:

Method 1: Calculate Mean by One Group

proc sql;
    select var1, mean(var2) as mean_var2
    from my_data
    group by var1;
quit;

Method 2: Calculate Mean by Multiple Groups

proc sql;
    select var1, var2, mean(var3) as mean_var3
    from my_data
    group by var1, var2;
quit;

The following examples show how to use each method with the following dataset in SAS:

/*create dataset*/
data my_data;
    input team $ position $ points;
    datalines;
A Guard 15
A Guard 12
A Guard 29
A Forward 13
A Forward 9
A Forward 16
B Guard 25
B Guard 20
B Guard 34
B Forward 19
B Forward 3
B Forward 8
;
run;

/*view dataset*/
proc printdata=my_data;

Example 1: Calculate Mean by One Group

The following code shows how to calculate the mean of points by team:

/*calculate mean of points by team*/
proc sql;
    select team, mean(points) as mean_points
    from my_data
    group by team;
quit;

From the output we can see that players on team A scored a mean of 15.66667 points and players on team B scored a mean of 18.16667 points.

Example 2: Calculate Mean by Multiple Groups

The following code shows how to calculate the mean of points, group by team and position:

/*calculate mean of points, grouped by team and position*/
proc sql;
    select team, position, mean(points) as mean_points
    from my_data
    group by team, position;
quit;

Additional Resources

The following tutorials explain how to perform other common tasks in SAS: