-----WEIGHTED TRIMMED MEAN (LET)------------------------------------
 
WEIGHTED TRIMMED MEAN
 
Name:
    WEIGHTED TRIMMED MEAN (LET)
 
Type:
    Let Subcommand
 
Purpose:
    Compute the weighted trimmed mean for a variable.
 
Description:
    The mean is the sum of the observations divided by the number of
    observations.  The mean can be heavily influenced by extreme values
    in the tails of a variable.  The weighted trimmed mean compensates for this
    by dropping a certain percentage of values on the tails.  For
    example, the 50% weighted trimmed mean is the mean of the values between
    the upper and lower quartiles.  The 90% weighted trimmed mean is the mean
    of the values after truncating the lowest and highest 5% of the
    values.
 
Syntax:
    LET <par> = WEIGHTED TRIMMED MEAN <y1> <SUBSET/EXCEPT/FOR qualification>
    where <y1> is the response variable;
          <par> is a parameter where the computed weighted trimmed mean is
                stored;
    and where the <SUBSET/EXCEPT/FOR qualification> is optional.
 
Examples:
    LET A = WEIGHTED TRIMMED MEAN Y1
    LET A = WEIGHTED TRIMMED MEAN Y1 SUBSET TAG > 2
 
Note:
    The analyst must specify the percentages to trim in each tail.
    This is done by defining the internal variables P1 (the lower
    tail) and P2 (the upper tail).  For example, to trim 10% off each
    tail, do the following:
        LET P1 = 10
        LET P2 = 10
        LET A = WEIGHTED TRIMMED MEAN Y
 
Default:
    None
 
Synonyms:
    None
 
Related Commands:
    WEIGHTED TRIMMED MEAN PLOT  = Generate a weighted trimmed mean vs. subset plot.
    MEAN                        = Compute the mean.
    WINDSORIZED MEAN     = Compute the Windsorized mean.
    MEDIAN               = Compute the median.
    STANDARD DEVIATION   = Compute the standard deviation.
 
Applications:
    Robust Data Analysis
 
Implementation Date:
    2003/5
 
Program:
    LET Y1 = CAUCHY RANDOM NUMBERS FOR I = 1 1 100
    LET P1 = 10
    LET P2 = 10
    LET A1 = WEIGHTED TRIMMED MEAN Y1
 
