Displays the fit of a linear, generalized linear, generalized additive or nonlinear model.
|What to print (
||Channel number of file, or identifier of a text to store output; default current output file|
||Whether to base ratios in accumulated summary on rms from model with smallest residual ss or smallest residual ms (
||Which warning messages to suppress (
||Printing of probabilities for variance and deviance ratios (
||Printing of probabilities for t-statistics (
||Statistics to be displayed in the summary of analysis produced by
||Dispersion parameter to be used as estimate for variability in s.e.s; default is as set in the
||Type of residuals to display (
||Basis of estimate of dispersion, if not fixed by
||Probability level for confidence intervals for parameter estimates; default 0.95|
||allows you to specify the number of degrees of freedom for a dispersion parameter specified by the
||Specifies save structure of model to display; default
RDISPLAY produces further output from a linear, generalized linear, generalized additive or nonlinear model. The
FIT directive, except that no monitoring is available. The
CHANNEL option selects the output channel to which the results are output, as in the
PROBABILITY options are also as in the
RMETHOD option allows you temporarily to change the method of forming residuals, for the output of the current statement only, in the same way as the corresponding option in the
MODEL directive sets the default method of formation. Similarly, the
DMETHOD option temporarily changes the method used to calculate the residual variability to be displayed for a generalized linear model, the
DISPERSION option allows you (temporarily) to set the dispersion parameter, and the
DFDISPERSION option allows you to define the number of degrees of freedom for a specified dispersion parameter. These again operate like the corresponding options of
MODEL (except that they apply only to the current statement).
SAVE option lets you specify the identifier of a regression save structure; the output will then relate to the most recent regression model fitted with that structure.
Commands for: Regression analysis.
" Example FIT-1: Simple linear regression Modelling the relationship between counts of apples from 12 trees (recorded as 100s of fruit) and percentage damage by codling moth. (Snedecor & Cochran, Statistical analysis, 1980, p162.)" VARIATE [VALUES= 8, 6,11,22,14,17,18,24,19,23,26,40] Cropsize & [VALUES=59,58,56,53,50,45,43,42,39,38,30,27] Wormy DGRAPH Wormy; Cropsize " It is expected that the larger the crop is the less the damage will be, since the density of the flying moths is unrelated to the crop size. Try fitting a linear model relating the percentage of damage directly to the size of the crop." MODEL Wormy FIT Cropsize " Tree number 4 seems different from the rest: perhaps it was not adequately protected by the standard spraying programme, or was on the side from which the codling moths flew in to the orchard. Tree number 12 has a much larger crop than the rest: the results of the regression are strongly influenced by this one observation. Display all the fitted values, residuals and leverages (influence)." RDISPLAY [PRINT=fittedvalues] " Check the effect of omitting tree number 4." RESTRICT Wormy; .NOT.EXPAND(4; 12) FIT [PRINT=summary] Cropsize " Return to the complete dataset, and display the fitted line." RESTRICT Wormy FIT [PRINT=*] Cropsize RGRAPH [GRAPHICS=high] " Plot the fitted values against the residuals, to check that the variance is roughly constant; use the procedure RCHECK from the Genstat Procedure Library." RCHECK [GRAPHICS=high] residual; fittedvalues