Plots residuals from a `REML`

analysis (S.J. Welham).

### Options

`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 |

### Parameters

`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 |

### Description

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`

.

Options: `RMETHOD`

, `INDEX`

, `GRAPHICS`

, `TITLE`

, `SAVE`

.

Parameters: `METHOD`

, `PEN`

.

### Method

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

Procedures: `VDEFFECTS`

, `VDFIELDRESIDUALS`

, `VFRESIDUALS`

, `VGRAPH`

, `APLOT`

, `DRESIDUALS`

, `RCHECK`

.

Commands for: REML analysis of linear mixed models.

### Example

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 VARIATE [NVALUES=50] Yield 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. : VCOMPONENTS [FIXED=Treats] RANDOM=Reps+Blocks REML [PRINT=*] Yield; SAVE=S VPLOT fitted,normal,halfnormal,histogram