Data Management

ON THIS PAGE

The ASP Data Editor
Working With Files
Working With Data Matrices
Variable Transformations
Case Transformations
Recoding Variables

The ASP Data Editor

Most routines in ASP require that data be contained in a data matrix. A data matrix is a rectangular array made up of columns and rows. Variables are identified with the columns of the matrix, and cases (i.e., the values of variables that correspond to each other) are identified with the rows.

Data matrices used by ASP contain only numbers. Thus, nonnumeric data (e.g., sex, political affiliation, etc.) must be given a numeric code (e.g., Male=1, Female=2, etc.) if they are to be included in an ASP data matrix.

The ASP data editor is used to create and modify ASP data matrices. This editor appears at the bottom of the opening screen when ASP is first started:

ASP Opening Screen/Data Editor.

open.gif (11392 bytes)

At the top of the editor is a frame containing a set of buttons and two edit boxes:

The edit boxes allow you to assign a file label and file name to the data matrix in the editor.
The buttons allow you to initiate various data management routines directly without having to go though the Windows menu system. By clicking on these buttons you can:
- Create a new data matrix.
- Open an existing data matrix.
- Save the data matrix in the editor.
- Add file information to the data matrix in memory.
- List the data matrix in the editor.
- Add variables to the data matrix in the editor either directly or from a file.
- Add cases to the data matrix in the editor either directly or from a file.
- Delete variables from the data matrix in the editor.
- Delete cases from the data matrix in the editor.
- The More Options button calls a menu of additional data management options. These options include:
  - Transforming variables and cases.
  - Transposing the data matrix in the editor.
  - Breaking down one variable by the values of another.
  - Combining a set of variables into a single variable.
  - recoding the values of a set of variables.

At the bottom of the editor are three grid boxes:

The grid box on the left allows you to enter case labels.
The grid box at the top allows you to enter variable names.
The main grid box on the lower right allows you to enter numeric data.

There is also an ENTER DATA By Case or By Var. option control above the grid box on the left. This option control allows you to enter data one case at a time if the By Case option is selected, or one variable at a time if the By Var. option is selected.

Once a data matrix is in the editor you can edit it as you see fit. You can use the scroll bars to the right and below the numeric grid box to bring any given cell in the data matrix into view, then click on the cell to open the edit window over the cell. You can also use the cursor keys to move the edit window to any cell in the data matrix.

TOP

Working With Files

ASP allows a great deal of flexibility in working with files. In addition to saving and opening files that are created in the ASP data editor, you can open and save the data in ASCII files along with the names of the variables in the data matrix being opened or saved. In addition, you can import data from the clipboard into the ASP data editor.

TOP

Working With Data Matrices

ASP allows you to transform and recode variables and cases, sort and transpose data matrices, breakdown and combine variables, add and delete variables and cases, and to generate variables to add to the data matrix. These routines are available on the DATA MANAGEMENT menu.

The options on this menu are also available directly in the ASP data editor on the opening screen. Four of the options on the DATA MANAGEMENT menu, adding and deleting variables and cases, are available directly from the data editor by clicking on the Add Vars, Add Cases, Delete Vars, or Delete Cases buttons in the frame at the top of the editor. (The data matrix in the editor can also be listed and printed in this way by clicking on the List Matrix and Print Matrix buttons.) The rest of the options on the DATA MANAGEMENT menu are on the more options menu obtained by clicking on the More Options button.

Eight of the options on the DATA MANAGEMENT menu allow you to operate directly on the data matrix in the editor:

Add Variables.
Add Cases.
Delete Variables.
Delete Cases.
Sort Data Matrix.
Transpose Data Matrix.
Combine Variables.
Break Down Variables.
TOP

Variable Transformations

The variable transformation options are located on the VARIABLE/CASE TRANSFORMATION menu. This menu has twenty-four options. These options allow you to generate:

Absolute values, reciprocals, and copies of variables.
Squares, square roots, and linear combinations of variables.
Relational variables between constants and other variables.
Logarithmic and anti logarithmic transformations of variables.
Lags, differences, and percent changes in variables
Trigonometric transformations of variables.
Cumulative, standardized, ranked, scaled, and mean deviations of variables.
Variable creating transformations:
- Trend/case number variables.
- Seasonal dummy variables.
- Breakdown dummy variables.
- Random samples from 20 probability distributions.
- Pattern variables.
TOP

Case Transformations

The Case Transformations option on the Variable/Case Transformations menu allows you to calculate the case statistics for a set of variables. The available statistics include the:

Mean and median.
Maximum and minimum.
Number of non-missing values.
Sum, sum of squares, and sum of squared deviations.
Variance and sample variance.
Standard error and sample standard error.
Coefficient of variation and sample coefficient of variation.
TOP

Recoding Variables

The Recode Variables option on the DATA MANAGEMENT menu allows you to systematically change the values of a set of variables.

TOP