960.390 - Introduction to Computers for Statistics, PROC MEANS

960.390 - Introduction to Computers for Statistics

960.390-02, Fall 1997, M 7,8 (6:10-9:00pm), Hill Center, Room 013
Meeting dates: 10/13, 10/20, 10/27, 11/3, 11/10

PROC MEANS

PROC MEANS is the first of the real-world functions that everybody uses. It's usage, though is very simple:

proc means data=mydata;
run;

This generates a table which displays, for each variable in the data set; the number of observations with the variable not missing, the mean, the standard deviation and the minimum and maximum values.

You can limit the variables by adding a line like "var height weight;" as an instruction/parameter line. You can change which statistics are printed by putting in different options:

Option What it causes to be included
MAX the maximum value of the variable
MEAN the mean value of the variable
MIN the minimum value of the variable
N the number of observations with the variable not missing
NMISS the number of observations with the variable missing
RANGE the range values of the variable
STD the standard deviation of the variable
SUM the sum of the values of the variable

Option	What it causes to be included
MAX	the maximum value of the variable
MEAN	the mean value of the variable
MIN	the minimum value of the variable
N	the number of observations with the variable not missing
NMISS	the number of observations with the variable missing
RANGE	the range values of the variable
STD	the standard deviation of the variable
SUM	the sum of the values of the variable

For example:

options linesize=78 nodate formdlim="-";
data form;
input low high profit;
cards;
432 433 35.23
532 533 24.32
632 633 -87.20
732 733 0.32
;
proc means mean n std sum data=form;
var low profit;
run;

produces output:

------------------------------------------------------------------------------
 
                                The SAS System                               1

            Variable          Mean  N       Std Dev           Sum
            -----------------------------------------------------
            LOW        582.0000000  4   129.0994449       2328.00
            PROFIT      -6.8325000  4    55.5272470   -27.3300000
            -----------------------------------------------------

Similarly to the PROC PRINT command, it is possible to do calculations with a "by varname;" style. Again, the data should be sorted by the variable before the MEANS procedure is run. Like this:

options linesize=78 nodate formdlim="-";
data form;
input low high profit;
if (profit < 0) then ouch = "YES";
else ouch = "NO";
cards;
432 433 35.23
532 533 24.32
632 633 -7.20
732 733 0.32
832 633 -5.43
;
proc sort data=form;
by ouch;
run;
proc means mean std sum data=form;
var profit;
by ouch;
run;

producing output:

------------------------------------------------------------------------------
 
                                The SAS System                               1

                   Analysis Variable : PROFIT


----------------------------------- OUCH=NO ----------------------------------


                           Mean       Std Dev           Sum
                   ----------------------------------------
                     19.9566667    17.8593402    59.8700000
                   ----------------------------------------

----------------------------------- OUCH=YES ---------------------------------


                           Mean       Std Dev           Sum
                   ----------------------------------------
                     -6.3150000     1.2515790   -12.6300000
                   ----------------------------------------

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