PLOT subcommand (ANOVA-F command)

PLOT provides a variety of plots useful in checking the assumptions needed in the analysis. The PLOT subcommand can be specified more than once. All of the plots requested on each PLOT subcommand are produced.

Use the following keywords on the PLOT subcommand to request plots:

SPREADLEVEL
Spread-versus-level plots. Plots of observed cell means versus standard deviations, and versus variances.
RESIDUALS
Observed by predicted by standardized residuals plot. A plot is produced for each dependent variable. In a univariate analysis, a plot is produced for the single dependent variable.
PROFILE
Plot of dependent variable means for one-way, two-way, or three-way crossed factors. The PROFILE keyword must be followed by parentheses containing a list of one or more factor combinations. All factors specified (either individual or crossed) must be made up of only valid factors on the factor list. Factor combinations on the PROFILE keyword may use an asterisk (*) or the keyword BY to specify crossed factors. A factor cannot occur in a single factor combination more than once.
  • The order of factors in a factor combination is important, and there is no restriction on the order of factors. If a single factor is specified after the PROFILE keyword, a line plot of estimated means at each level of the factor is produced. If a two-way crossed factor combination is specified, the output includes a multiple-line plot of estimated means at each level of the first specified factor, with a separate line drawn for each level of the second specified factor. If a three-way crossed factor combination is specified, the output includes multiple-line plots of estimated means at each level of the first specified factor, with separate lines for each level of the second factor, and separate plots for each level of the third factor.
  • The PROFILE keyword may be followed by the WITH keyword and a parenthesized list of covariates and values. Plots are produced with the values of the covariates fixed at the specified values. The keyword MEAN causes the covariate to be fixed at its observed mean value.
TYPE=LINE | BAR
Type of plot for profile plots. The default type is LINE.
ERRORBAR=NO | CI | SE (value)
Include error bars in the profile plot. The default setting is NO.
CI
Error bars display the confidence interval. The confidence interval is determined by the ALPHA value on the CRITERIA subcommand. The confidence interval is 1-alpha. For example, if the ALPHA value is 0.05, the confidence interval is 95%.
SE (value)
Error bars display standard errors. The default value is 2. The value must be a positive number.

Example

ANOVA-F DEP BY A B 
  /PLOT = SPREADLEVEL PROFILE(A A*B A*B*C) WITH(X=1.0)
  /DESIGN.

Assume each of the factors A, B, and C has three levels.

  • Spread-versus-level plots are produced showing observed cell means versus standard deviations and observed cell means versus variances.
  • Five profile plots are produced. For factor A, a line plot of estimated means at each level of A is produced (one plot). For the two-way crossed factor combination A*B, a multiple-line plot of estimated means at each level of A, with a separate line for each level of B, is produced (one plot). For the three-way crossed factor combination A*B*C, a multiple-line plot of estimated means at each level of A, with a separate line for each level of B, is produced for each of the three levels of C (three plots). Plots are produced with the value of the covariate X fixed at 1.0.