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Dataplot Vol 2 Vol 1

WEIGHTED SUM OF DEVIATIONS FROM THE MEAN

Name:
    WEIGHTED SUM OF DEVIATIONS FROM THE MEAN (LET)
Type:
    Let Subcommand
Purpose:
    Compute the weighted sum of deviations from the mean of a variable.
Description:
    The weighted sum of deviations from the mean is defined as

      WDEV = SUM[i=1 to N][W(i)*(X(i) - XBAR)]

    where X is the response variable, W is the weights variable, and XBAR is the sample mean. The response variable and weights variable must have the same number of observations.

    For this command, the weights are not normalized. However, at least one of the weights must be positive and none of the weights can be negative. Otherwise, an error message is reported.

Syntax:
    LET <par> = WEIGHTED SUM OF DEVIATIONS FROM THE MEAN <x> <w>
                            <SUBSET/EXCEPT/FOR qualification>
    where <x> is the response variable;
                <w> is the weights variable;
                <par> is a parameter where the weighted sum of deviations from the mean is saved;
    and where the <SUBSET/EXCEPT/FOR qualification> is optional.
Examples:
    LET A = WEIGHTED SUM OF DEVIATIONS FROM THE MEAN Y1 WEIGHT
    LET A = WEIGHTED SUM OF DEVIATIONS FROM THE MEAN Y1 WEIGHT SUBSET Y1 > 0
Note:
    Dataplot statistics can be used in a number of commands. For details, enter

Default:
    None
Synonyms:
    None
Related Commands: Applications:
    Data Analysis
Implementation Date:
    2012/06
Program:
     
    LET Y = DATA 2 3 5 7 11 13 17 19 23
    LET W = DATA 1 1 0 0 4 1 2 1 0
    .
    LET A = WEIGHTED SUM OF DEVIATIONS FROM THE MEAN Y W
        
    The returned value is 3.8889.

Date created: 06/29/2012
Last updated: 06/29/2012
Please email comments on this WWW page to alan.heckert@nist.gov.