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VPLOT procedure

Plots residuals from a REML analysis (S.J. Welham).


RMETHOD = string token Which random terms to use when calculating the residuals (final, all, notspline, stfinal, stall); default uses the setting from the REML statement
INDEX = variate or factor X-variable for an index plot; default !(1,2...)
GRAPHICS = string token What type of graphics to use (lineprinter, highresolution); default high
TITLE = text Overall title for the plots; if unset, the identifier of the y-variate is used
SAVE = REML save structure Specifies the (REML) save structure from which the residuals and fitted values are to be taken; default * uses the SAVE structure from the most recent REML analysis


METHOD = string tokens Type of residual plot (fittedvalues, normal, halfnormal, histogram, absresidual, index); default fitt, norm, half, hist
PEN = scalars, variates or factors Pen(s) to use for each plot


Procedure VPLOT provides up to four types of residual plots from a REML analysis. These are selected using the METHOD parameter, with settings: fitted for residuals versus fitted values, normal for a Normal plot, halfnormal for a half-Normal plot, histogram for a histogram of residuals, absresidual for a plot of the absolute values of the residuals versus the fitted values, and index for a plot against an “index” variable (specified by the INDEX option). The PEN parameter can specify the graphics pen or pens to use for each plot. The TITLE option can supply an overall title. If this is not set, the identifier of the y-variate is used.

The residuals and fitted values are accessed automatically from the analysis specified by the SAVE option. If the SAVE option has not been set, they are taken from the SAVE structure from the most recent REML analysis.

The RMETHOD option controls which random terms are used to calculate the residuals:

    all all the random effects,
    final only the final random term,
    notspline all except any random spline terms,
    stall standardized residuals using all the random effects, and
    stfinal standardized residuals using only the final random term.

The default takes the setting from the REML directive that produced the analysis. Note that residuals based on the final random term will not be calculated when any of the variance components are negative, as the associated negative correlations can generate very misleading patterns. VPLOT will then generate a warning that all the residuals are missing, and you should use RMETHOD=all instead.

By default, high-resolution graphics are used. Line-printer graphics can be used by setting option GRAPHICS=lineprinter.


Parameters: METHOD, PEN.


Residuals and fitted values effects are accessed, using VKEEP or VFRESIDUALS, from the REML analysis specified by the SAVE option. The plots are produced using the DRESIDUALS procedure.

Action with RESTRICT

If the y-variate in the REML analysis was restricted, then only units included by the restriction will be used in the graphs.

See also


Commands for: REML analysis of linear mixed models.


CAPTION 'VPLOT example',\ 
        !t('Incomplete block design, data from Cochran & Cox',\ 
        '(1957), Experimental Designs, p. 406.'); STYLE=meta,plain
FACTOR  [LEVELS=2; VALUES=25(1,2)] Reps
 &      [LEVELS=10; VALUES=5(1...10)] Blocks
 &      [LEVELS=25; VALUES=1...25,1,6...21,2,7...22,3,8...23,4,9...24,\ 
        5,10...25] Treats
READ    Yield
   6.   7.   5.   8.   6.  16.  12.  12.  13.   8.
  17.   7.   7.   9.  14.  18.  16.  13.  13.  14.
  14.  15.  11.  14.  14.  24.  13.  24.  11.   8.
  21.  11.  14.  11.  23.  16.   4.  12.  12.  12.
  17.  10.  30.   9.  23.  15.  15.  22.  16.  19.
REML        [PRINT=*] Yield; SAVE=S
VPLOT       fitted,normal,halfnormal,histogram
Updated on March 4, 2019

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