SED navigation bar go to SED home page go to Dataplot home page go to NIST home page SED Home Page SED Staff SED Projects SED Products and Publications Search SED Pages
Dataplot Vol 2 Vol 1

RANK INDEX

Name:
    RANK INDEX (LET)
Type:
    Let Subcommand
Purpose:
    Compute the ranks of a variable where each rank will be a unique integer value.
Description:
    When the RANK command encouters ties in the response variable, all tied values are given the same average rank. For example, if ranks 5 and 6 denote the same value, then each would be assinged a rank of 5.5.

    The RANK INDEX command performs ranking. However, it handles ties differently. For example, if ranks 5 and 6 denote the same value, this command will return 5 and 6 as the ranks rather than 5.5 for both.

    This command is useful when you want to use the rank as an index to another variable. An example is given in the program example below.

Syntax:
    LET <y> = RANK INDEX <x>             <SUBSET/EXCEPT/FOR qualification>
    where <x> is the variable for which the ranks are to be computed;
                <y> is a variable where the computed ranks are saved;
    and where the <SUBSET/EXCEPT/FOR qualification> is optional.
Examples:
    LET Y = RANK INDEX X
Default:
    None
Synonyms:
    None
Related Commands:
    RANK = Rank the elements in a variable.
    RANK2 = Rank the elements in a variable where there is grouping in the data.
    SORT = Sort the elements in a variable.
    SORTC = Sort the elements in a variable and carry one or more variables along.
Applications:
    Nonparametric statistics
Implementation Date:
    2010/6
Program:
     
    skip 25
    read splett2.dat y x
    let string s1 = Tinius1
    let string s2 = Tinius2
    let string s3 = Satec
    let string s4 = Tokyo
    .
    let xsort iindx = sort by median y x
    set let cross tabulate collapse
    let y2 = cross tabulate median y x
    let x2 = rank index y2
    loop for k = 1 1 4
        let ival = x2(k)
        let string t^ival = ^s^k
    end of loop
    x1tic mark label case asis
    x1tic mark label format alpha
    x1tic mark label content ^t1 ^t2 ^t3 ^t4
    .
    char box plot
    line box plot
    fences on
    .
    xlimits 1 4
    major xtic mark number 4
    minor xtic mark number 0
    xtic offset 0.5 0.5
    .
    title case asis
    title offset 2
    title Charpy V-NIST Notch Testing
    label case asis
    x1label Machine Manufacturer
    y1label Absorbed Energy
    .
    box plot y xsort
        
    plot generated by sample program

Date created: 9/8/2010
Last updated: 9/8/2010
Please email comments on this WWW page to alan.heckert@nist.gov.