Analysis of a Robust Design Experiment - Quick Tab

Analyzing Taguchi Designs

Select the Quick tab of the Analysis of a Robust Design Experiment dialog to access options to quickly review the results of your analysis.

Summary: Analysis of variance

Click the Summary: Analysis of variance button to display an interactive spreadsheet with the ANOVA summary table. The specific MS residual in this table is used subsequently in the summary Plot of means (see below) to establish confidence intervals. Options for adding interactions and pooling terms are available on the ANOVA tab. Note that the choices made on that tab affect the Plot of means.

Eta under optimum conditions

Click the Eta under optimum conditions button to display an interactive spreadsheet for predicting Eta given specific settings (levels) of some or all factors. This option is useful for designing and evaluating verification experiments (Introductory Overview). The expected S/N ratio is displayed in the last line of the spreadsheet. Several options are available for this spreadsheet on the Optimum eta tab.

Marginal means

Click the Marginal means button to display a spreadsheet with the marginal means, parameter estimates, standard deviations, and standard errors for each level for each factor. These descriptive statistics pertain to the average Eta values (S/N ratios), not to the untransformed variables. The parameter estimates can be interpreted as deviations of the means from the overall mean Eta value (m) for the respective levels of the respective factors. For example, a parameter estimate of lA1 = 1.5 for level 1 of factor A means that, all other things being equal, setting this factor to this level resulted in a mean of m + lA1.

Plot of means

Click the Means plot button to display a plot of means for each factor in the design. In this plot, optimum settings for each factor can be easily identified. Note that the 2 * standard error limits in this plot (indicated by the dashed lines) are based on the MS residual computed from the factors that were selected into the model the last time that either the Summary: Analysis of variance option on the ANOVA tab or Eta under optimum conditions option on the Accumulation Analysis Results - Optimum Eta tab were selected. By default (if neither one of these options has previously been used), all main effects are included in the model.