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.