Input Formats
in Correspondence Analysis  Frequencies without Grouping Variables
If the Frequencies w/out grouping
vars option button is selected [from the Input
group box on either the Correspondence Analysis (CA): Table Specifications
Startup Panel  Correspondence
Analysis (CA) tab or the Multiple Correspondence Analysis (MCA): Table
Specifications Startup Panel
 Multiple Correspondence Analysis (MCA) tab], STATISTICA
expects that the selected variables (and cases) contain frequency values
only (or some other measure of correspondence).
Selection
of variables for simple correspondence analysis.
If a simple
correspondence analysis is specified, STATISTICA
will treat each selected variable as a category or level of a categorical
(column) variable, and each case as a category or level of a second categorical
(row) variable. For example, the data in the example file Smoking.sta
are organized in this manner:
CASE
NAME 
NONE 
LIGHT 
MEDIUM 
HEAVY 
SR.
MANAGERS 
4 
2 
3 
2 
JR.
MANAGERS 
4 
3 
7 
4 
SR.
EMPLOYEES 
25 
10 
12 
4 
JR.
EMPLOYEES 
18 
24 
33 
13 
SECRETARIES 
10 
6 
7 
2 
Note that the column variables denote different categories for the (categorical)
variable "Smoking frequency."
Selection of variables and codes
for multiple correspondence analysis. If a multiple
correspondence analysis is selected, then the data in the selected
variables (and cases) are expected to define a valid Burt
table (see MCA
Introductory Overview). For example, the following data specify a
valid Burt table:

Survival 

Age 

Location 
NO 
YES 
<50 
5069 
69+ 
TOKYO 
BOSTON 
GLAMORGN 
SURVIVAL:NO 
210 
0 
68 
93 
49 
60 
82 
68 
SURVIVAL:YES 
0 
554 
212 
258 
84 
230 
171 
153 





AGE:UNDER_50 
68 
212 

280 
0 
0 

151 
58 
71 
AGE:A_50TO69 
93 
258 
0 
351 
0 
120 
122 
109 
AGE:OVER_69 
49 
84 
0 
0 
133 
19 
73 
41 





LOCATION:TOKYO 
60 
230 

151 
120 
19 

290 
0 
0 
LOCATION:BOSTON 
82 
171 
58 
122 
73 
0 
253 
0 
LOCATION:GLAMORGN 
68 
153 
71 
109 
41 
0 
0 
221 
The Burt
table has a clearly defined structure. Overall, the data matrix is
symmetrical. In the case of 3 categorical variables, the data matrix consists
of 3 x 3 = 9 partitions, created by each variable being tabulated against
itself, and against the categories of all other variables. Note that the
sum of the diagonal elements in each diagonal partition (i.e., where the
respective variables are tabulated against themselves) is constant (equal
to 764 in this case). Technically, the Burt table is the result of the
inner product of an indicator or design
matrix; if the cases in that indicator matrix are assigned to categories
via fuzzy coding (i.e., if probabilities are used to indicate likelihood
of membership in a category, rather than 0/1 coding to indicate actual
membership), then the offdiagonal elements of the diagonal partitions
are not necessarily equal to 0. Note that complex coding schemes can easily
be implemented, and the respective Burt table computed, via STATISTICA
Visual Basic. Refer also to MCA
Introductory Overview for additional details.
In addition to selecting the variables for the analysis, you also need
to specify the structure of the Burt table. Click the Specify
structure of table button (on the Multiple Correspondence Analysis (MCA): Table
Specifications Startup Panel
 Multiple Correspondence Analysis (MCA) tab) to display the
Specify
the dimensions of the table dialog, in which you specify the
factor names (e.g., survival, age, location) and the number of levels
for each factor (e.g., 2, 3, and 3).
When processing the data, STATISTICA
will automatically check whether the respective data specify a valid Burt
table. Note that the Specify structure
of table button is only available after Variables
have been selected.
In addition to the variables defining the table for the analysis, you
can designate some variables as Supplementary
columns (variables). Note that unlike in simple
correspondence analysis, where supplementary columns and rows can
be added from the Correspondence
Analysis Results  Supplementary points
tab, in multiple
correspondence analysis it is required that the supplementary columns
also define a valid Burt table. Therefore, in this case, click the Variables with frequencies button [on
the Multiple Correspondence Analysis (MCA): Table
Specifications Startup Panel
 Multiple Correspondence Analysis (MCA) tab] to specify all
variables for the analysis, and then click the Supplementary
columns (variables) button to display the Select
the Variables that are Supplementary Column dialog, in which you
select a subset of those variables as supplementary columns. When processing
the data, STATISTICA will automatically
check whether the selected subset of variables define a valid subset (Burt
table) of the overall Burt
table. The variables selected as supplementary columns will not be
used for the computation of eigenvalues
and eigenvectors (see Computational
Details), but coordinate values will be computed for those columns
and reported in the spreadsheet and plots of coordinates.