DIFFERENCE OF GEOMETRIC SD

DIFFERENCE OF GEOMETRIC SD (LET)

Let Subcommand

Compute the difference between the geometric standard deviations for two response variables.

The geometric standard deviation is defined as:

For the difference of geometric standard deviations, the geometric standard deviation is computed for each of two samples then their difference is taken. Syntax:

LET <par> = DIFFERENCE OF GEOMETRIC SD <y1> <y2>
                        <SUBSET/EXCEPT/FOR qualification>
where <y1> is the first response variable;
            <y2> is the first response variable;
            <par> is a parameter where the computed difference of the geometric standard deviations is stored;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

LET A = DIFFERENCE OF GEOMETRIC SD Y1 Y2
LET A = DIFFERENCE OF GEOMETRIC SD Y1 Y2 SUBSET X > 1

The difference of geometric sds statistic is also supported for the following commands:
DIFFERENCE OF GEOMETRIC SD PLOT Y1 Y2 X
CROSS TABULATE DIFFERENCE OF GEOMETRIC SD PLOT Y1 Y2 X
BOOTSTRAP DIFFERENCE OF GEOMETRIC SD PLOT Y1 Y2
TABULATE DIFFERENCE OF GEOMETRIC SD Y1 Y2 X
CROSS TABULATE DIFFERENCE OF GEOMETRIC SD Y1 Y2 X
LET Z = CROSS TABULATE DIFFERENCE OF GEOMETRIC SD Y1 Y2 X1 X2


Enter

HELP STATISTIC PLOT HELP CROSS TABULATE PLOT HELP BOOTSTRAP PLOT HELP TABULATE HELP CROSS TABULATE HELP CROSS TABULATE (LET)

for more information on these plots and commands.

None

None

GEOMETRIC SD	= Compute the geometric sd.
GEOMETRIC MEAN	= Compute the geometric mean.
STANDARD DEVIATION	= Compute the standard deviation.
DIFFERENCE OF MEAN	= Compute the difference of the means.
DIFFERENCE OF GEOMETRIC MEAN	= Compute the difference of the geometric means.
DIFFERENCE OF SD	= Compute the difference of standard deviations.
DIFFERENCE OF QUANTILE	= Compute the difference of a quantile.
STATISTICS PLOT	= Generate a statistic versus subset plot.
CROSS TABULATE PLOT	= Generate a statistic versus two subsets plot.
BOOTSTRAP PLOT	= Generate a bootstrap plot.
TABULATE	= Perform a tabulation for a specified statistic.
CROSS TABULATE	= Perform a cross tabulation for a specified statistic.

Data Analysis

3/2003

SKIP 25  
READ IRIS.DAT Y1 TO Y4 X  
.  
LET A = DIFFERENCE OF GEOMETRIC SD Y1 Y2  
TABULATE DIFFERENCE OF GEOMETRIC SD Y1 Y2 X  
.  
XTIC OFFSET 0.2 0.2 
X1LABEL GROUP ID 
Y1LABEL DIFFERENCE OF GEOMETRIC SDS 
CHAR X  
LINE BLANK  
DIFFERENCE OF GEOMETRIC SD PLOT Y1 Y2 X  
. 
CHAR X ALL  
LINE BLANK ALL  
BOOTSTRAP DIFFERENCE OF GEOMETRIC SD PLOT Y1 Y2 X   
    

Dataplot generated the following output.

       ************************************************
       **  LET A = DIFFERENCE OF GEOMETRIC SD Y1 Y2  **
       ************************************************
  
  
 THE COMPUTED VALUE OF THE CONSTANT A             = -0.21327734E-02
  
  
       ***************************************************
       **  TABULATE DIFFERENCE OF GEOMETRIC SD Y1 Y2 X  **
       ***************************************************
  
  
                 *    Y1       AND Y2
     X           *    DIFFERENCE OF GEOMETRIC SD
 **********************************************
     1.00000     *   -0.462339E-01
     2.00000     *   -0.331452E-01
     3.00000     *   -0.122206E-01
  
       GROUP-ID AND STATISTIC WRITTEN TO FILE DPST1F.DAT