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Geometric Mean and Harmonic Mean in SAS

How does one compute Geometric Mean of a column in a SAS dataset? Also Harmonic mean?
It seems possible to compute GM of a row in SAS, but that would require using PROC TRANSPOSE. I couldn't find how to compute this directly for one or more columns. It seems surprising that this fairly mundane descriptive statistic.

thanks in advance.

- stochastic

andymcooper

Stochastic,

You're right - proc means will not do this. Why not???
Anyway, I think will the following SAS code will.
Note - comment out all lines using PRODUCT if you have a lot of variables >1, otherwise the numbers get too big!

/* dataset to try code on */
data tst;
length VAR 8.;
do VAR=1 to 10;
output;
end;
run;

/* datastep to calculate all sorts of means */
data tst_m (keep=ARITHMETIC_MEAN GEOMETRIC_MEAN_A GEOMETRIC_MEAN_B HARMONIC_MEAN);
set tst end=EOF;
retain COUNT PRODUCT SUM SUM_LOGS SUM_INV;

length COUNT PRODUCT SUM SUM_LOGS SUM_INV ARITHMETIC_MEAN GEOMETRIC_MEAN_A GEOMETRIC_MEAN_B HARMONIC_MEAN 8.;

LOG_VAR = log(VAR);

/* initialise to 0 */
if _N_=1 then do;
COUNT= 0 ;
PRODUCT=1;
SUM_LOGS = 0;
SUM =0 ;
SUM_INV = 0;
end;

/* note - product gets too big in most cases, so sum logs instead */
COUNT=COUNT+1;
PRODUCT=PRODUCT*VAR;
SUM_LOGS=SUM_LOGS+LOG_VAR;
SUM=SUM+VAR;
SUM_INV=SUM_INV+1/VAR;

if EOF then do;
ARITHMETIC_MEAN = SUM/COUNT;
GEOMETRIC_MEAN_A = PRODUCT**(1/COUNT);
GEOMETRIC_MEAN_B = exp((1/COUNT)*SUM_LOGS);
HARMONIC_MEAN = 1/(SUM_INV/COUNT);
output;
end;
run;

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andymcooper

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stochastic

ASKER

andymcooper,

I apologize for the delayed response. Thanks for your suggestions, I will try them out. Meanwhile
I'm accepting your comment as a solution. What remains is the curiosity about why this isn't a built-in feature.

- stochastic