DIFFERENCE OF AAD

DIFFERENCE OF AAD (LET)

Let Subcommand

Compute the difference between the average absolute deviations (AAD) for two response variables.

The average absolute deviation is defined as

with denoting the mean of the variable and n denoting the number of observations. This statistic is sometimes used as an alternative to the standard deviation.

For the difference of average absolute deviations, the average absolute deviation is computed for each of two samples then their difference is taken.

LET <par> = DIFFERENCE OF AAD <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 average absolute deviations is stored;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

LET A = DIFFERENCE OF AAD Y1 Y2
LET A = DIFFERENCE OF AAD Y1 Y2 SUBSET X > 1

The difference of average absolute deviations statistic is also supported for the following commands:
DIFFERENCE OF AAD PLOT Y1 Y2 X
CROSS TABULATE DIFFERENCE OF AAD PLOT Y1 Y2 X
BOOTSTRAP DIFFERENCE OF AAD PLOT Y1 Y2
TABULATE DIFFERENCE OF AAD Y1 Y2 X
CROSS TABULATE DIFFERENCE OF AAD Y1 Y2 X
LET Z = CROSS TABULATE DIFFERENCE OF AAD 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

AVERAGE ABSOLUTE DEVIATION is a synonym for AAD.

AAD	= Compute the average absolute deviation.
MAD	= Compute the median absolute deviation.
STANDARD DEVIATION	= Compute the standard deviation.
DIFFERENCE OF MAD	= Compute the difference of median absolute deviations.
DIFFERENCE OF SD	= Compute the difference of standard deviations.
DIFFERENCE OF BIWEIGHT SCALE	= Compute the difference of biweight scales.
DIFFERENCE OF BIWEIGHT MIDVARIANCES	= Compute the difference of biweight midvariances.
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

3/2002

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

Dataplot generated the following output.

       ***************************************
       **  LET A = DIFFERENCE OF AAD Y1 Y2  **
       ***************************************
  
  
 THE COMPUTED VALUE OF THE CONSTANT A             =  0.35400003E+00
  
  
       ******************************************
       **  TABULATE DIFFERENCE OF AAD Y1 Y2 X  **
       ******************************************
  
  
                 *    Y1       AND Y2
     X           *    DIFFERENCE OF AVERAGE ABSOLUTE
 **********************************************
     1.00000     *   -0.140000E-01
     2.00000     *    0.170000
     3.00000     *    0.254000
  
       GROUP-ID AND STATISTIC WRITTEN TO FILE DPST1F.DAT