General ANOVA/MANOVA - Quick Tab

Ribbon bar. Select the Statistics tab. In the Base group, click ANOVA to display the General ANOVA/MANOVA dialog box.

Classic menus. On the Statistics menu, select ANOVA to display the General ANOVA/MANOVA dialog box.

The dialog box contains one tab, Quick, which contains options to select the desired method of analysis (see also, General ANOVA/MANOVA - Index). In order to perform a General ANOVA/MANOVA analysis, a data file must be selected at this point.

For more information, refer to the Introductory Overview. See also General ANOVA/MANOVA - Index or Methods for Analysis of Variance. For related ANOVA and regression methods, refer also to GLM, DOE and Variance Components.

OK. Click the OK button to display an analysis specification dialog box, which differs depending on the Specification method selected on the Quick tab.

Cancel. Click the Cancel button to close the dialog box without performing an analysis.

Options. See Options Menu for descriptions of the commands on this menu.

Open Data. Click the Open Data button to display the Select Data Source dialog box, which contains options to choose the spreadsheet on which to perform the analysis. The Select Data Source dialog box contains a list of the spreadsheets that are currently active.

Select Cases. Click the Select Cases button to display the Analysis/Graph Case Selection Conditions dialog box, which is used to create conditions for which cases will be included (or excluded) in the current analysis. More information is available in the case selection conditions overview, syntax summary, and dialog box description.

W. Click the W (Weight) button to display the Analysis/Graph Case Weights dialog box, which contains options to adjust the contribution of individual cases to the outcome of the current analysis by "weighting" those cases in proportion to the values of a selected variable.

Weighted moments. Select the Weighted moments check box to specify that each observation contributes the weighting variable's value for that observation. The weight values need not be integers. This module can use fractional case weights in most computations. Some other modules use case weights as integer case multipliers or frequency values. This check box will only be available after you have defined a weight variable via the W option above.

DF = W-1 / N-1. When the Weighted moments check box is selected, moment statistics (e.g., mean, variance) can be based on the sum of the weight values for the weighting variable (W-1), or on the number of (unweighted) observations (N-1). The sums of squares and cross products will always be based on the weighted values of the respective observations. However, in computations requiring the degrees of freedom (e.g., standard deviation, ANOVA tables), the value for the degrees of freedom can either be computed based on the sum of the weight values, or based on the number of observations. Moment statistics are based on the sum of the weight values for the weighting variable if the W-1 option button is selected, and are based on the number of (unweighted) observations if the N-1 options button is selected. For more information on options for using integer case weights, see also Define Weight.

 

Quick Tab

The Quick tab of the General ANOVA/MANOVA dialog box contains options to select the desired method of analysis. In order to perform a General ANOVA/MANOVA analysis, a data file must be selected at this point.

This tab presents a list of common experimental analysis designs (in the Type of analysis list; see also Methods for Analysis of Variance), and provides access to the three different user interfaces available in the STATISTICA General ANOVA/MANOVA module via the Specification method list [these user interfaces are also available in the Statistica General Linear Models (GLM), General Regression Models (GRM), Generalized Linear/Nonlinear Models (GLZ), and General Partial Least Squares Models (PLS) modules].

Type of analysis. The Type of Analysis list presents four choices for the type of ANOVA/MANOVA analysis model (see the Introductory Overview). Select the type of design that you want to perform. For more information on a particular type of analysis, click on the link below.

Specification method. The Specification method list presents the three alternative user interfaces available in ANOVA/MANOVA.

Quick specs dialog. Select Quick specs dialog to use the respective Quick Specs dialog box corresponding to the selection in the Type of analysis box. The Quick Specs dialog box will prompt you to select dependent variable(s) and categorical predictor variables (depending on the selection in the Type of analysis box), and construct a default model. Use the options on the Quick Specs dialog box - Options tab to modify various computational specifications, or click the Syntax editor button to further customize the model via command syntax (see Analysis Syntax).

Analysis Wizard. Select Analysis Wizard to use a sequence of dialog boxes that will guide you through the steps for specifying an analysis. At the conclusion of the sequence of dialog boxes, you can either compute the results or click the Syntax editor button to further customize the model via command syntax, open an existing file with command syntax, or save syntax in a file for future repetitive use.

Analysis syntax editor. Select Analysis syntax editor to specify a model via the MAN Analysis Syntax Editor, which provides various options for specifying designs and for modifying various parameters of the computational procedures. You can also open an existing text file with command syntax, or save syntax in a file for future repetitive use. Refer to the description of the Analysis Syntax Editor and the description of the MANOVA Syntax for additional details.

Note: between-groups designs. In order to specify a between-groups design, at least one dependent variable must be selected, at least one categorical predictor (grouping variable) must be selected, and at least two independent variable codes must be specified (via the Factor codes button, which can be found on both the ANOVA/MANOVA Quick Specs - Quick tab and the MAN Analysis Wizard Extended Options - Quick tab) for each between-groups factor. Note that if you do not explicitly specify the codes, by default, Statistica will use as codes all values encountered in the specified independent variables.

Note: within-groups designs. In order to specify a repeated measures factor design, at least two dependent variables must be selected, and the repeated measures factor has to be identified via the Within effects button available on the ANOVA/MANOVA Quick Specs - Quick tab. Multiple dependent variables that cannot be interpreted (by Statistica, given the design you specified) as levels of repeated measures factors are interpreted as multiple dependent variables in a MANOVA design (this will occur if, for example, you select two or more dependent variables and do not define them as repeated measures, or whenever you select more dependent variables than can be accounted for by the currently defined repeated measure factor and its levels). Note that if you have multiple repeated measures factors, you must use the GLM module.

Note: Empty Cell Designs. ANOVA/MANOVA will automatically handle designs with empty cells. To analyze Latin squares, Greco-Latin squares, or other balanced incomplete designs, simply specify them as if they were complete factorial designs. Then specify the design as a Main effects ANOVA, to estimate the main effects. In order to analyze unbalanced missing cell designs, or complex "messy" designs (as, for example, discussed in Milliken & Johnson, 1992) choose the appropriate type of method for constructing hypotheses by selecting one of the Sums of squares options from the ANOVA/MANOVA Quick Specs - Options tab; for a detailed discussion of how to analyze such designs, refer to the GLM Six types of sums of squares topic.

Note: Huge Balanced ANOVA Designs. Most between ANOVA designs can be analyzed much more efficiently when they are balanced, i.e., when all cells in the ANOVA design have equal N, when there are no missing cells in the design. Statistica GLM contains an option to "instruct" the program that the design is balanced, and that the more efficient computational methods can be used. Even very large designs with effects with degrees of freedom in the hundreds can thus be analyzed in mere seconds, while the general computational procedures (that do not assume a balanced design) may take several minutes to accomplish the same. See Efficient Computations for (Huge) Balanced ANOVA Designs in the GLM Introductory Overview for additional details.

For more information, refer to the Introductory Overview. See also ANOVA/MANOVA - Index or Methods for Analysis of Variance.