Dataplot Vol 2 Vol 1

# DIFFERENCE OF GEOMETRIC SD

Name:
DIFFERENCE OF GEOMETRIC SD (LET)
Type:
Let Subcommand
Purpose:
Compute the difference between the geometric standard deviations for two response variables.
Description:
The geometric standard deviation is defined as:

$$\mbox{GSD} = e^{sd(\log{X_i})}$$

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.
Examples:
LET A = DIFFERENCE OF GEOMETRIC SD Y1 Y2
LET A = DIFFERENCE OF GEOMETRIC SD Y1 Y2 SUBSET X > 1
Note:
Dataplot statistics can be used in a number of commands. For details, enter

Default:
None
Synonyms:
None
Related Commands:
 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. BOOTSTRAP PLOT = Generate a bootstrap plot. TABULATE = Perform a tabulation for a specified statistic.
Applications:
Data Analysis
Implementation Date:
2003/03
Program:
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


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Date created: 03/27/2003
Last updated: 11/09/2015