Each PC-MDS diskette contains a number of programs. The label identifies the programs contained on each diskette. Also on each diskette is a matching test data set of the same name as the program. For example, one diskette will contain several programs, one of which is the KYST program, with files named:

KYST.EXE (The executable program file) and

KYST.DAT (The sample data file)

Other programs contain a file with an .SPS or .CTL extension. These are sample control files that contain the commands used by the program. The file COMMANDS.SPS contains a sample listing of the SPSS^*type commands used by the programs FREQuency, REGRESSion, FACTOR and DISCRIMinant.

The program user should copy the program and associated sample data and command files to the machine's hard drive. The master diskettes are intended only as backup diskettes and not as the diskettes from which the programs are to be run. This is because each program writes an output file to diskette and there is not room for output on the master diskette.

RUNNING PC-MDS PROGRAMS

Each PC-MDS program operates independently from all other programs. To run a given program, for example KYST, place the diskette containing the KYST program in a disk drive (Drive A is assumed) and type the program name:

A>KYST

Each PC-MDS program allows the user to interact with the program in identifying input parameters for each analysis. The program logo will appear, identifying the program name and the registered user. After selecting the continue option, the user is typically required to specify a (1) a TITLE for the program, (2) the name and location for the data file, and (3) the name and location of the output file. This is shown in the following menu prompts from the KYST program:

ENTER THE TITLE OF ANALYSIS (80 SPACES MAXIMUM)

ENTER THE NAME OF THE RAW DATA INPUT FILE

USE THE FORM: DRV:FILENAM.EXT (e.g. B:DATA.DAT)

ENTER THE NAME OF THE OUTPUT DISK FILE

SPECIFY THE DRIVE AND FILE NAME (e.g. B:RUN1.PRN)

The input and output file names should contain the full Path name. For example, if the sub-directory MDPREF on the C: drive contains the file "DATA1.DAT", the file name would be entered as

C:\MDPREF\DATA1.DAT

The file name may be up to 50 characters long.

All output, including statistical and plot results, is saved to a user specified disk file. Several programs may be run and analyses saved for later evaluation and printing. Each output file is written in ASCII (Text characters) format, and is suitable for editing with any word processor. When calling a PC-MDS output file into your word processor or editor, treat the file as a DOS TEXT FILE, (should this information be required) and set your margins left and right to 1 and 132.

PRINTING PC-MDS OUTPUT

The easiest way to print an output file is to load the file into your word processor and set the font to courier 8 or Lineprinter and adjust the margins so that each line of the output does not wrap to the next line.

Alternatively, output may be directed to a printer by pressing the ENTER key instead of giving a name when asked for the OUTPUT DISK FILE. A third, more archaic means of printing is to use the PRINT command from a DOS window by typing:

A>PRINT FILENAM.EXT

Where FILENAM.EXT is the name and extension of the OUTPUT DISK FILE. An alternate approach not requiring the DOS disk is to COPY the OUTPUT DISK FILE to the printer by specifying the logical printer name (LPT1 if a parallel printer): A>COPY FILENAM.EXT LPT1

PC-MDS INPUT: PARAMETERS AND FORMATS

Parameter Input: PC-MDS requires the use of a parameter line for most programs. The specific program documentation indicates whether or not a parameter line is required at all, or if parameters may be entered from the keyboard.

Parameters, if required are entered as the first line of the data file. All programs, except CORAN will accept parameters in FREE format (Formatting is explained in the next section). For example, the example input file for KYST appears:

5 1 1
(5F5.3)
  9.3 0.57  6.1  2.0  1.5 
  1.0  8.5  5.5  3.3  4.0 
  2.1  5.3  7.3  3.9  1.1 
  5.0  6.2  1.6  8.9  2.8 
  1.3  4.1  1.0  2.5  8.8

where the first line is the parameter line, the second line contains the FORTRAN format statement, and the third and successive lines contain the data.

Preparing A Format Statement: Format statements tell PC-MDS how the data file is to be read for a single observation or respondent. Format statements are prepared using the standard FORTRAN language coding conventions. These conventions are quite simple and easy to learn.

1. Begin and end a format statement with open and closed parentheses "(" and ")".

2. All programs require what is termed an "F" format (F stands for real floating point number format). Real floating point numbers are numbers that may or may not have decimal points.

3. The format statement simply identifies how many variables of a given type are to be read in a row and the number of columns each number takes in the data file. The notation conventions will now be explained. Remember that a comma should separate each of the different types of notation entities, and that blanks are read as zeros.

All data entries are read as fixed format, meaning that the same information must be in the same place for each new line of data.

Microsoft FORTRAN requires, when reading a half matrix, that all data for each row be on one row of the data file. For example, if the lower half (below the diagonal) of a 50 x 50 matrix is to be read, the format statement might appear: (50F8.5). This would mean that 50 items are read from each line, even though many would be blank in the upper portion of the matrix.

COMPLETE EXAMPLES:

FREE FORMAT: The parameter lines on each of the programs may be entered in FREE format. Free format means that each parameter value is separated by at least one blank space.

PC-MDS INPUT: 3-D Graphics

PC-MDS 5.1 introduced 3-D Graphics to multidimensional scaling and correspondence analysis. Following the analysis and two dimensional plots, each program that produces mapping output invokes the graphics mode and displays the plot of the first three dimensions.

Creating Labels: Labels may be included as part of the plots. They are defined by including the labels after the data for the scaling input. In the example of MDPREF, found below, we have a matrix of 8 brands that are defined as points (the columns of the matrix) and 6 attributes that are defined as vectors (the rows of the matrix). Up to 50 total points + vectors may be plotted. In the case of a program such as KYST, which has only points and no vectors, 50 points may be plotted. The data input for specific programs may vary, but for all programs (MDPREF, KYST, PREFMAP, INDSCAL, PROFIT and CORRESP) the labels follow the data. One label is entered per line. In the case of no label for a particular row or column, insert a blank line. In the example below, the program reads the first 8 labels as column labels and the next 6 labels as row labels.

Labels are limited in length to 9 characters. You will want to make the labels as short as possible, especially when there are many points and vectors to be plotted. Too many labels that are too long make for messy graphs.

A program called GRAFPLUS.COM is included on the program diskettes for printing in DOS mode. It is, however much easier to (1) print directly from Windows using the Print Screen keyboard button, (2) to copy a graph into memory using the keys, or (3) to use a screen capture program to simply scrape what is on the screen and put it into a file. If you are using the GRAFPLUS.COM program, the program must be in the same subdirectory or diskette as the program you are running. GRAFPLUS is a program that defines your printer and provides the graphics interface between the 3-D graphics program and your printer. Many of the newer printers are not defined by the program.

When the 3-D program begins, it asks you if you want to print the images. If you respond "YES", then you may select the printer interface for DOS printing (Window's users won't want to do this). If you Respond "NO", then the program proceeds with the 3-D plots, but does not set up the printer interface. Do not set up the printer interface if you are using windows. Instead, use a capture program to capture the graphics image and send it to a file. Several screen capture programs are available either as part of other software packages or as a no charge download through the Internet. Each of these programs create graphics files that can be imported into other programs with graphics printing capabilities such as Microsoft Powerpoint, Adobe PhotoShop, Corel PhotoPaint, or graphics program.

Example MDPREF data set with labels

   6   8   3   2   1   0
 (5X, 8F2.0)
011   5 2 8 1 3 7 6 4
012   2 1 3 6 4 7 8 5
021   4 7 1 8 6 2 3 5
022   2 5 4 8 3 6 1 7
031   7 4 5 1 6 3 8 2
032   8 3 6 5 1 7 2 4
 Taste
 Price
 Color
 Sparkle
 Colaness
 Image
 Coke
 Pepsi
 RC
 Shasta
 Jolt
 Canada
 OurBrand
 Cragmont 

Theta = angle from vertical axis 
Phi = angle from horizontal plane 
Inc = change in view for each keystroke 
The arrow keys rotate the figure. 
Home rotates up and left; 
PgUp rotates up and right;
End rotates down and left;
PgDn rotates down and right 
Enter resets the graph to the original view