UNIT 19 COMPUTER DATA ANALYSIS
Structure
19.1 Introduction
19.2. Objectives
19.3 What is SPSS?
19.4 Get Yourself Acquainted with SPSS
19.5 Menu Commands and Sub-commands
19.6 Basic Steps in Data Analysis
19.7 Defining, Editing and Entering Data
19.8 Data File Management Functions
19.8.1 Merging Data Files
19.82 Aggregate Data
19.8.3 Split File
19.8.4 Select Cases
19.9 Running a Preliminary Analysis
19.9.1 Six Characteristics of a Dataset
19.92 Data Transformation
19.9.3 Exploring Data
19.9.4 Graphical Presentation of Data
19.9.5 Scatterplots and Histograms
19.10 Understanding Relationship Between Variables
19.10.1 The Mean Procedure
19.10.2 Linear Regression
19.10.3 Curve Estimation
19.11 Non-parametric Tests
19.12 SPSS Production Facility
19.13 Satistical Analysis System (SAS)
19.14 NUDIST
19.15 Let Us Sum Up
19.16 Unit-end Activities
19.17 Suggested Readings
19.18 Answers to Check Your Progress
Appendix
19.1 INTRODUCTION
In earlier units, we provided you with a detailed understanding of how quantitative
and qualitative data are analysed manually. Although some of us still carry out
analysis of data manually, the advent of sophisticated computer software has made
data analysis more convenient and easier. Earlier, the software which could only
be run on large mainframe computers can now be run with considerable ease on
the PCs. SPSS is one such software which is used in educational research. You
can analyze large and computer data files with thousands of variables on your PC
without compromising the quality and the precision of analysis. 109
,Data Analysis and In this unit, we will introduce you to the software for quantitative and qualitative
Interpretation data analysis. We will provide in this details of SPSS package which is comparatively
more popular among research students for quantitative data analysis. We will also
introduce in this unit the Statistical Analysis System (SAS), another software for
quantitative data analysis. We will introduce a software called NUDIST for
qualitative data analysis.
19.2 OBJECTIVES
After going through this Unit, you should be able to:
a explain describe the main features of the SPSS;
a write about as well as use the data management operations and techniques of
analysis using SPSS;
a acquire skills in the use of SPSS for basic statistical analysis with a special
focus on the measures of central tendency, dispersion, correlation and
regression; and
a present the data and the SPSS results graphically.
19.3 WHAT IS SPSS ?
SPSS* is one of the leading desktop statistical packages. It is an ideal companion
to the database and spreadsheet, combining many of their features as well as adding
its own specialized hnctions. SPSS for windows is available, as a base module and
a number of optional add-on enhancements are also available. Some versions present
SPSS as an integrated package including the base and some important add-on-
modules.
SPSS Professional Statistics provides techniques to examine similarities and
dissimilarities in data and to classify.data, identify underlying dimensions in a data
set. It includes procedures for cluster, k-cluster, discriminating factor, multi-
dimensional scaling, and proximity and reliability analysis.
SPSS Advanced Statistics includes procedures for logistic regression, log-linear
analysis, multivariate analysis and analysis of variance. This module also includes
procedures for constrained non-linear regression, probit, Cox and actuarial survival
analysis.
SPSS Tables creates a high quality presentation-quality tabular reports including
stub and banner tables and display. of multiple response data sets. The new features
include pivot tables, a valuable tool for presentation of selected analytical output
tables.
SPSS Trends performs comprehensive forecasting and time series analysis with
multiple curve fitting models, smoothing models and methods for estimation of
autoregressive functions.
SPSS categories performs conjoint analysis and optional scaling procedures, including
correspondence analisis.
SPSS Chaid provides simplified tabular analysis of categories data, develops
predictive models, screens out extraneous predictor variables, and produces easy to
110 SPSS is registered trademark o f the SPSS Corporation, USA.
,read tree diagrams that segment a population into sub-groups that share similar Computer Data Analysis
characteristics.
Recently, the SPSS Corporation announced the release of SPSS version 8.0. Many
new add-on products have also been launched in the recent months. You can consult
the SPSS World Wide Web site for the latest developments and additions to the
computing power SPSS. Technical support is also available to the registered user at
the SPSS site. The SPSS Web site is http://www.spss.com. Select white papers on
SPSS applications in major disciplines are also available on this site.
SPSS version 7.5 for Windows is now available with most users across the globe.
The present unit discusses some of the commonly used data management techniques
and statistical procedures using SPSS 7.5. Since new features are added almost
daily, you are advised to check for these details on the currently installed version of
SPSS on your computer and also consult the user manuals before undertaking
complex type of data analysis. The on-line help is also available. There may be
some procedures and syntax related changes from one version to another. We will
attempt to provide you with procedures that are most commonly used with SPSS
Release 7.5. In case these are not available on your version of SPSS, please consult
the relevant SPSS authorized representative or the WWW site of the SPSS
corporation.
19.4 GET YOCTRSELFACQUAINTED WITH SPSS
The SPSS for Windows can be run from Windows 98 through Windows XP operating
systems. Unix, Mac and mainframe versions of the SPSS software are also available.
The illustrations in this Unit are based on SPSS version for Window 95/98/NT
operating systems.
Starting SPSS
The SPSS for Windows uses graphical environment, descriptive menus and simple
dialog boxes to do most of the work. It produces three type of files, namely data
files, chart files and text files.
To start SPSS, click the start button on your Compute$. On the start menu that
appears, click Program. Another menu appears on the right of the start menu. If
there is an entry marked SPSS, that's the one you want to click. If there isn't, click
the program group where SPSS was installed and an entry marked SPSS will appear.
Click the SPSS 7.5 entry. You will know when the SPSS has started and SPSS
Data Editor window appears. To begin with, the SPSS data editor window will be
empty and a number of menus will appear on the top of the window. You will start
the operations by loading a data set or by creating a new file for which data is to
be entered from the data editor window. The data can also be imported from other
programs like Dbase, ASCII, Excel and Lotus.
Existing SPSS
Make sure that all SPSS and other files are saved before quitting the program. You
should exit the software by shutting off the program by selecting Exit SPSS command
from the file menu of the SPSS Data Editor window. In case of unsaved files, the
SPSS will prompt you to save or discard the changes in the file.
2 It is assumed that a proper licensed and valid version of SPSS is already installed on the computer
you are working with. 111
, Data Analysis and Saving data and other files
Interpretation
Many types of file can be saved using 'save' or 'save as' command. Various types
of files used in SPSS are: Data, Syntax, Chart or Output. Files from spreadsheets
or other databases can also be imported by following the appropriate procedure.
Similarly, an SPSS file can be saved as a spreadsheet or in dbase format. Select
the appropriate save type command and save the file. The SPSS data files are
saved with .sav as the secondary name. Though SPSS files could be given any
name, the use of reserved words and symbols is to be avoided in all types of file
names.
Printing of data and output files
The contents of SPSS data files,. Output Navigator files and Syntax Files can be
printed using the standard 'Print' command. The SPSS uses the default printer for
printing. In the case of network printers, an appropriate printer should be selected
for printing the output. It is suggested that Ink jet or Laser jet printers should be
used for printing graphs and.charts. Tabular data can be easily printed using a Dot
matrix Printer.
Operating Windows in SPSS
There are seven types of Windows in SPSS which are frequently referred to during
the data management and analysis stages. These are:
Data Editor
As mentioned earlier, the data editor window opens automatically as soon the SPSS
gets loaded. To begin with, the data editor does not contain any data. The file
containing the data for analysis has to be loaded with the help of the 'file' menu
sub-commands by using various options available for this purpose. The contents of
the active data file are displayed in the data editor window. Only one data editor
window will be active at a time. No statistical operations can be performed until
some data is loaded into data editor.
Output Navigator
All SPSS messages, statistical results, tables and charts are displayed in the output
navigator. The output in the navigator Window can be edited and saved for future
reference. The Output Navigator opens automatically, the first time some output is
generated. The user can customize the presentation of reports and tables displayed
in the Output Navigator. The output can be directly imported into reports prepared
under word processing packages, and the output files are saved with an extension
xxxx.spo.
Pivot Tables
The output shown in the Output Navigator can be modified in many ways using the
Edit and Pivot Table Option, which can be used to edit text, swap rows and column,
add colour, prepare custom made reportsloutput, create and display selectively multi-
dimensional tables. The results can be selectively hidden and shown using features
available in Pivot Tables.
Graphics
The Chart Editor helps in switching between various types of charts, swapping of
X-Y axis, changing colour and providing facilities for presenting data and results
through various type of graphical presentations.
It is useful for customizing the charts to highlight specific features of the charts and
112 map.
Structure
19.1 Introduction
19.2. Objectives
19.3 What is SPSS?
19.4 Get Yourself Acquainted with SPSS
19.5 Menu Commands and Sub-commands
19.6 Basic Steps in Data Analysis
19.7 Defining, Editing and Entering Data
19.8 Data File Management Functions
19.8.1 Merging Data Files
19.82 Aggregate Data
19.8.3 Split File
19.8.4 Select Cases
19.9 Running a Preliminary Analysis
19.9.1 Six Characteristics of a Dataset
19.92 Data Transformation
19.9.3 Exploring Data
19.9.4 Graphical Presentation of Data
19.9.5 Scatterplots and Histograms
19.10 Understanding Relationship Between Variables
19.10.1 The Mean Procedure
19.10.2 Linear Regression
19.10.3 Curve Estimation
19.11 Non-parametric Tests
19.12 SPSS Production Facility
19.13 Satistical Analysis System (SAS)
19.14 NUDIST
19.15 Let Us Sum Up
19.16 Unit-end Activities
19.17 Suggested Readings
19.18 Answers to Check Your Progress
Appendix
19.1 INTRODUCTION
In earlier units, we provided you with a detailed understanding of how quantitative
and qualitative data are analysed manually. Although some of us still carry out
analysis of data manually, the advent of sophisticated computer software has made
data analysis more convenient and easier. Earlier, the software which could only
be run on large mainframe computers can now be run with considerable ease on
the PCs. SPSS is one such software which is used in educational research. You
can analyze large and computer data files with thousands of variables on your PC
without compromising the quality and the precision of analysis. 109
,Data Analysis and In this unit, we will introduce you to the software for quantitative and qualitative
Interpretation data analysis. We will provide in this details of SPSS package which is comparatively
more popular among research students for quantitative data analysis. We will also
introduce in this unit the Statistical Analysis System (SAS), another software for
quantitative data analysis. We will introduce a software called NUDIST for
qualitative data analysis.
19.2 OBJECTIVES
After going through this Unit, you should be able to:
a explain describe the main features of the SPSS;
a write about as well as use the data management operations and techniques of
analysis using SPSS;
a acquire skills in the use of SPSS for basic statistical analysis with a special
focus on the measures of central tendency, dispersion, correlation and
regression; and
a present the data and the SPSS results graphically.
19.3 WHAT IS SPSS ?
SPSS* is one of the leading desktop statistical packages. It is an ideal companion
to the database and spreadsheet, combining many of their features as well as adding
its own specialized hnctions. SPSS for windows is available, as a base module and
a number of optional add-on enhancements are also available. Some versions present
SPSS as an integrated package including the base and some important add-on-
modules.
SPSS Professional Statistics provides techniques to examine similarities and
dissimilarities in data and to classify.data, identify underlying dimensions in a data
set. It includes procedures for cluster, k-cluster, discriminating factor, multi-
dimensional scaling, and proximity and reliability analysis.
SPSS Advanced Statistics includes procedures for logistic regression, log-linear
analysis, multivariate analysis and analysis of variance. This module also includes
procedures for constrained non-linear regression, probit, Cox and actuarial survival
analysis.
SPSS Tables creates a high quality presentation-quality tabular reports including
stub and banner tables and display. of multiple response data sets. The new features
include pivot tables, a valuable tool for presentation of selected analytical output
tables.
SPSS Trends performs comprehensive forecasting and time series analysis with
multiple curve fitting models, smoothing models and methods for estimation of
autoregressive functions.
SPSS categories performs conjoint analysis and optional scaling procedures, including
correspondence analisis.
SPSS Chaid provides simplified tabular analysis of categories data, develops
predictive models, screens out extraneous predictor variables, and produces easy to
110 SPSS is registered trademark o f the SPSS Corporation, USA.
,read tree diagrams that segment a population into sub-groups that share similar Computer Data Analysis
characteristics.
Recently, the SPSS Corporation announced the release of SPSS version 8.0. Many
new add-on products have also been launched in the recent months. You can consult
the SPSS World Wide Web site for the latest developments and additions to the
computing power SPSS. Technical support is also available to the registered user at
the SPSS site. The SPSS Web site is http://www.spss.com. Select white papers on
SPSS applications in major disciplines are also available on this site.
SPSS version 7.5 for Windows is now available with most users across the globe.
The present unit discusses some of the commonly used data management techniques
and statistical procedures using SPSS 7.5. Since new features are added almost
daily, you are advised to check for these details on the currently installed version of
SPSS on your computer and also consult the user manuals before undertaking
complex type of data analysis. The on-line help is also available. There may be
some procedures and syntax related changes from one version to another. We will
attempt to provide you with procedures that are most commonly used with SPSS
Release 7.5. In case these are not available on your version of SPSS, please consult
the relevant SPSS authorized representative or the WWW site of the SPSS
corporation.
19.4 GET YOCTRSELFACQUAINTED WITH SPSS
The SPSS for Windows can be run from Windows 98 through Windows XP operating
systems. Unix, Mac and mainframe versions of the SPSS software are also available.
The illustrations in this Unit are based on SPSS version for Window 95/98/NT
operating systems.
Starting SPSS
The SPSS for Windows uses graphical environment, descriptive menus and simple
dialog boxes to do most of the work. It produces three type of files, namely data
files, chart files and text files.
To start SPSS, click the start button on your Compute$. On the start menu that
appears, click Program. Another menu appears on the right of the start menu. If
there is an entry marked SPSS, that's the one you want to click. If there isn't, click
the program group where SPSS was installed and an entry marked SPSS will appear.
Click the SPSS 7.5 entry. You will know when the SPSS has started and SPSS
Data Editor window appears. To begin with, the SPSS data editor window will be
empty and a number of menus will appear on the top of the window. You will start
the operations by loading a data set or by creating a new file for which data is to
be entered from the data editor window. The data can also be imported from other
programs like Dbase, ASCII, Excel and Lotus.
Existing SPSS
Make sure that all SPSS and other files are saved before quitting the program. You
should exit the software by shutting off the program by selecting Exit SPSS command
from the file menu of the SPSS Data Editor window. In case of unsaved files, the
SPSS will prompt you to save or discard the changes in the file.
2 It is assumed that a proper licensed and valid version of SPSS is already installed on the computer
you are working with. 111
, Data Analysis and Saving data and other files
Interpretation
Many types of file can be saved using 'save' or 'save as' command. Various types
of files used in SPSS are: Data, Syntax, Chart or Output. Files from spreadsheets
or other databases can also be imported by following the appropriate procedure.
Similarly, an SPSS file can be saved as a spreadsheet or in dbase format. Select
the appropriate save type command and save the file. The SPSS data files are
saved with .sav as the secondary name. Though SPSS files could be given any
name, the use of reserved words and symbols is to be avoided in all types of file
names.
Printing of data and output files
The contents of SPSS data files,. Output Navigator files and Syntax Files can be
printed using the standard 'Print' command. The SPSS uses the default printer for
printing. In the case of network printers, an appropriate printer should be selected
for printing the output. It is suggested that Ink jet or Laser jet printers should be
used for printing graphs and.charts. Tabular data can be easily printed using a Dot
matrix Printer.
Operating Windows in SPSS
There are seven types of Windows in SPSS which are frequently referred to during
the data management and analysis stages. These are:
Data Editor
As mentioned earlier, the data editor window opens automatically as soon the SPSS
gets loaded. To begin with, the data editor does not contain any data. The file
containing the data for analysis has to be loaded with the help of the 'file' menu
sub-commands by using various options available for this purpose. The contents of
the active data file are displayed in the data editor window. Only one data editor
window will be active at a time. No statistical operations can be performed until
some data is loaded into data editor.
Output Navigator
All SPSS messages, statistical results, tables and charts are displayed in the output
navigator. The output in the navigator Window can be edited and saved for future
reference. The Output Navigator opens automatically, the first time some output is
generated. The user can customize the presentation of reports and tables displayed
in the Output Navigator. The output can be directly imported into reports prepared
under word processing packages, and the output files are saved with an extension
xxxx.spo.
Pivot Tables
The output shown in the Output Navigator can be modified in many ways using the
Edit and Pivot Table Option, which can be used to edit text, swap rows and column,
add colour, prepare custom made reportsloutput, create and display selectively multi-
dimensional tables. The results can be selectively hidden and shown using features
available in Pivot Tables.
Graphics
The Chart Editor helps in switching between various types of charts, swapping of
X-Y axis, changing colour and providing facilities for presenting data and results
through various type of graphical presentations.
It is useful for customizing the charts to highlight specific features of the charts and
112 map.
