2. Agenda
2
Introduction to SAS Software Program
Data preparation & Tabulation
Test of Difference: T-test, and ANOVA
Test of Association: Correlation & Regression Analysis
4. SAS
⢠From traditional statistical analysis of variance
and predictive modeling to exact methods and
statistical visualization techniques, SAS/STAT
software is designed for both specialized and
enterprise wide analytical needs. SAS/STAT
software provides a complete, comprehensive set
of tools that can meet the data analysis needs of
the entire organization.
4
5. SAS Components
5
SAS Enterprise
Guide
SAS Enterprise
Guide
SAS 9.2SAS 9.2
Graphical user interface application
for some common basic data analysis
tasks.
Graphical user interface application
for some common basic data analysis
tasks.
Command-based application for a
wide variety of data analysis tasks.
Command-based application for a
wide variety of data analysis tasks.
6. SAS Enterprise Guide
⢠To open the statistical software package SAS
go to the Start Menu >>> All Programs >>>
SAS >>> SAS Enterprise Guide 4.3
6
7. SAS 9.2
⢠To open the statistical software package SAS
go to the Start Menu >> All Program >> SAS
>> SAS 9.2 (English)
7
8. What Is SAS Enterprise Guide?
What Is SAS Enterprise Guide? SAS
Enterprise Guide is an easy-to-use Windows
client application that provides these features:
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â access to much of the functionality of SAS
â an intuitive, visual, customizable interface
â transparent access to data
â ready-to-use tasks for analysis and
reporting
â easy ways to export data and results to
other applications
â scripting and automation
â a program editor with syntax completion
and built-in function help
10. Create a Project for This Tutorial
⢠If SAS Enterprise Guide is not open, start it now. In the
Welcome window, select New Project.
⢠If SAS Enterprise Guide is already open, select File >>
New Project. If you already had a project open in SAS
Enterprise Guide, you might be prompted to save the
project. Select the appropriate response.
⢠The new project opens with an empty Process Flow
window.
10
11. 1. The Project Tree
⢠You can use the Project Tree window to manage
the objects in your project. You can delete,
rename, and reorder the items in the project.
You can also run a process flow or schedule a
process flow to run at a particular time.
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12. 2. Workspace and Process Flow Windows
You can have one or more
process flows in your project.
When you create a new project,
an empty Process Flow window
opens. As you add data, run
tasks, and generate output, an
icon for each object is added to
the process flow.
The process flow displays the
objects in a project, any
relationships that exist between
the objects, and the order in
which the objects will run when
you run the process flow.
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13. 3. The Task List
You can use tasks to do
everything from manipulating
data, to running specific
analytical procedures, to
creating reports.
Many tasks are also available as
wizards, which contain a
limited number of options and
can provide a quick and easy
way to use some of the tasks.
13
14. Add SAS Data to the Project
⢠You can add SAS data files
and other types of files,
including OLAP cubes,
information maps, ODBC-
compliant data, and files
that are created by other
software packages, such as
Microsoft Word or
Microsoft Excel.
14
15. ⢠SAS Enterprise Guide requires all data that it
accesses to be in table format. A table is a
rectangular arrangement of rows (also called
observations) and columns (also called
variables).
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Name Gender Age Weight
Jones M 48 128.6
Laverne M 58 158.3
Jaffe F . 115.5
Wilson M 28 170.1
16. ⢠a column's type is important because it affects how
the column can be used in a SAS Enterprise Guide
task. A column's type can be either character or
numeric.
⢠Character variables, such as Name and Gender in
the preceding data set, can contain any values.
Missing character values are represented by a blank.
⢠Numeric variables, such as Age and Weight in the
preceding data set, can contain only numeric values.
Currency, date, and time data is stored as numeric
variables. Missing numeric values are represented
by a period.
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Name Gender Age Weight
Jones M 48 128.6
Laverne M 58 158.3
Jaffe F . 115.5
Wilson M 28 170.1
17. Local and Remote Data
⢠When you open data in SAS Enterprise Guide,
you must select whether you want to look for the
data on your local computer, a SAS server, or in
a SAS folder.
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18. Local and Remote Data (Contâ)
⢠If you click My Computer, you can browse the
directory structure of your computer. You can
open any type of data file that SAS Enterprise
Guide can read.
⢠If you click Servers, you can look for your data
on a server. A server can either be a local server
if SAS software is installed on your own
computer, or it can be a remote server if SAS
software is installed on a different computer.
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19. Open Data from Server
⢠Within each server there are icons that you can select for
Libraries and Files. Libraries are shortcut names for
directory locations that SAS knows about. Some libraries
are defined by SAS, and some are defined by SAS
Enterprise Guide. Libraries contain only SAS data sets.
⢠The Files folder on a server enables you to access data
files in the directory structure on the computer where
the SAS server is running. For example, if you wanted to
open a Microsoft Excel file on a server that is defined in
your repository, you would use the Files node to locate
and open the file.
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20. Open Data from SAS Folders
If you click SAS Folders, you can browse the list
of SAS folders that you can access. SAS folders
are defined in the SAS Metadata Server and can
be used to provide a central location for your
stored processes, information maps, and projects
so that they can be shared with other SAS
applications. SAS folders can also contain content
that is not in the SAS Metadata Server, such as
data files.
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21. Add SAS Data from Your Local Computer
⢠Select File >> Open >> Data. In the Open Data
window, select My Computer.
⢠Open the SAS Enterprise Guide samples directory
and double-click Data. By default, the sample
programs, projects, and data are located in
C:Program FilesSASEnterpriseGuide4.3Sample.
By default, all file types are displayed in the
window. Files with the icon are SAS data sets.
Press CTRL and select Orders.sd2 and
Products.sas7bdat, and then click Open.
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22. Add SAS Data from Your Local Computer
(Contâ)
⢠Shortcuts to
the Products and Orders
tables are added to the
project, and the data sets
open in data grids.
⢠By default, the tables open in
read-only mode. In this
mode, you can browse, resize
column widths, hide and
hold columns and rows, and
copy columns and rows to a
new table.
⢠You cannot edit the data in
the table unless you change
to edit mode. Select Edit >>
Remove Protect Data
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23. View the Properties of a Data Set
⢠In the project tree, right-click Products and
select Properties from the pop-up menu. The
Properties for Products window opens. You can see
information about general properties such as the
physical location of the data and the date it was last
modified.
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24. View the Properties of a Data Set (Contâ)
⢠In the selection pane, click Columns. Here you
can view a list of columns in your data and the
column attributes.
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25. Add Data from a SAS Library
⢠Select File >> Open >> Data.
In the Open Data window,
select Servers.
⢠Double-click Libraries, and
then double-click SASHELP.
As you can see, only SAS data
sets are stored in libraries
⢠Scroll in the window and
double-click
the PRDSALE data set. A
shortcut to the data is added to
the project and the data opens
in the data grid.
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26. Save the Project
⢠Select File >> Save
Project As.
⢠The Save window opens
and prompts you to choose
whether to save the project
on your computer or on a
server. Select My
Computer.
⢠In the Save window, select a
location for the project. In
the File name box, type
âyour file nameâ. Project
files are saved with the
extension .egp.
⢠Click Save.
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30. What is a SAS Data Library?
⢠A SAS data library is a collection of one or more
SAS files that are recognized by SAS and can be
referenced and stored as a unit. Each file is a
member of the library. SAS data libraries help to
organize your work. For example, if a SAS
program uses more than one SAS file, then you
can keep all the files in the same library.
Organizing files in libraries makes it easier to
locate the files and reference them in a program.
30
31. Telling SAS Where the SAS Data
Library Is Located
⢠directly specify the operating environment's
physical name for the location of the SAS data
library.
⢠assign a SAS libref (library reference), which is a
SAS name that is temporarily associated with the
physical location name of the SAS data library.
31
32. Using Librefs for Temporary and
Permanent Libraries
⢠When you start a SAS session, SAS automatically
assigns the libref WORK to a special SAS data
library. Normally, the files in the WORK library
are temporary files.
⢠Files that are stored in any SAS data library
other than the WORK library are usually
permanent files; that is, they endure from one
SAS session to the next. Store SAS files in a
permanent library if you plan to use them in
multiple SAS sessions.
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33. Create a SAS Library
⢠Tools >> Assign Project Library
33
34. Create a SAS Library â Step 1
⢠Specify name and server for the library
34
35. Create a SAS Library â Step 2
⢠Specify the engine for the library
35
36. Create a SAS Library â Step 3
⢠Specify options for the library
36
37. Create a SAS Library â Step 4
⢠Click Test Library, checking itâs OK to create this library
⢠Press Finish to create the library
37
38. Create a SAS Library
⢠Check created library at
Server List
⢠When a libref is assigned to
a SAS data library, you can
use the libref throughout
the SAS session to access
the SAS files that are stored
in that library or to create
new files.
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40. Create SAS Data Set â Step 1
⢠Specify name âTESTâ and location âDEMOâ
40
41. Create SAS Data Set â Step 2
⢠Create columns and specify their properties
41
Name Gender Age Weight
Jones M 48 128.6
Laverne M 58 158.3
Jaffe F . 115.5
Wilson M 28 170.1
43. Import from an External File
⢠The Import Data wizard enables you to create
SAS data sets from text, HTML, or PC-based
database files (including Microsoft Excel,
Microsoft Access, and other popular formats).
When you use the Import Data wizard, you can
specify import options for each file that you
import.
43
56. Create Format (Contâ)
⢠Set Format Name âGENDERâ
⢠Select Library - SASUSER
⢠Select Format Type âCharacterâ
56
57. Define Formats
⢠Click New Label and type a name of a label
⢠Click New Range and select type of values and
type a value according to the specified label
⢠Repeat the steps
⢠Click Run
57
60. Applying User-Defined Formats (Contâ)
⢠In the left pane, select Formats
⢠In Categories box, select User Defined
⢠In Formats box, select the desired Formats
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61. Applying Formats in Tasks
⢠Custom formats can be applied in the same
places that formats defined in SAS can be used.
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62. SAS Tasks
⢠After you have data in your project, you can
create reports and run analyses on the data.
⢠To do this, you select a SAS task from the Task
List or from the Tasks menu. Some tasks have
wizards to guide you through the decisions that
you need to make. Wizards are available from
menus or from a link next to the related task in
the Task List.
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63. Using Tasks in SAS Enterprise Guide
⢠The icon next to each variable
represents the variable's type.
Country is a character
variable ( ). Year is a
numeric variable ( ). Month
is a numeric variable in date-
and-time format ( ). Actual
and Predict are numeric
variables in currency format
( ).
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64. One-Way Frequencies Task
We should create One-Way Frequencies (tables
and graphs) to check our data set one last time
before we intensively analyze the data.
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68. Filter and Sort
Use Tasks >> Data >> Filter and Sort... or Sort data...
to help you find the error(s).
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69. Summary Statistics Task
The Summary Statistics task can be used to
calculate summary statistics based on groups
within the data. You can produce reports,
graphs, and data sets as output.
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70. Summary Statistics Task
The Summary Statistics task has both a wizard
and the standard task dialog box that can be
used to set up the results.
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71. Summary Statistics: Task Roles
Use the wizard to assign variables to roles.
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Specify variables whose
values define subgroups.
Compute statistics
for each numeric
variable in the list.
72. Summary Statistics: Statistics and Results
Choose statistics and results to include, including
a report, graphics, and an output data set.
72
75. Summary Tables Wizard
The Summary Tables wizard enables you to select analysis
variable(s) and statistics, assign classification variables
to define rows and columns, and specify totals.
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82. T-Test Output
82
Since p-value is less than
0.05, it can be concluded that
average male students also
consider themselves as a
well-prepared students for
advising appointment
Since p-value is less than
0.05, it can be concluded that
average male students also
consider themselves as a
well-prepared students for
advising appointment
Since p-value is less than
0.05, it can be concluded that
average female students
consider themselves as a
well-prepared students for
advising appointment
(significantly higher than 3).
Since p-value is less than
0.05, it can be concluded that
average female students
consider themselves as a
well-prepared students for
advising appointment
(significantly higher than 3).
85. ⢠Under Data, choose Q6 as the analysis variable
task role and Gender as the classification
variable.
85
86. ⢠Under Plots, check Summary plot,
Confidence interval plot, and Normal
quantile-quantile (Q-Q) plot.
86
87. T-Test Output
87
the probability is greater than
0.05. So there is evidence
that the variances for the two
groups, female students and
male students, are not
different.
the probability is greater than
0.05. So there is evidence
that the variances for the two
groups, female students and
male students, are not
different.
Equaled variance is assumed.
Pooled method is used. Since
p-value is greater than 0.05,
it cannot be concluded that
there is significant difference
in Advisor Satisfaction
between male and female
students.
Equaled variance is assumed.
Pooled method is used. Since
p-value is greater than 0.05,
it cannot be concluded that
there is significant difference
in Advisor Satisfaction
between male and female
students.
91. ⢠Under Means Comparison, check
Bonferroni t test, Duncanâs multiple-
range test, and Scheffeâs multiple
comparison procedure for Post Hoc tests
91
92. ⢠Under Plots, check Means for Plots Types.
⢠Then, click Run.
92
93. One-Way ANOVA results
93
Since p-value is greater than 0.05,
it can be concluded that there is no
significant difference in average
Advisor Satisfaction among
year(s) of study. Therefore, there is
no need to check the Post Hoc tests.
Since p-value is greater than 0.05,
it can be concluded that there is no
significant difference in average
Advisor Satisfaction among
year(s) of study. Therefore, there is
no need to check the Post Hoc tests.
101. ⢠In Results, check the box for Create a scatter plot for
each correlation pair. Also, check the box at the right for
Show correlations in decreasing order of magnitude and
uncheck the box for Show statistics for each variable.
101
102. Correlation Analysis
102
⢠Since p-values are less than 0.05, there are
significant (positive) relationships between Q6
(Overall satisfaction on Advisor) and Q1, Q2,
Q3, Q4, Q5.
106. Regression: Statistics
⢠Under Details on estimates, check Standardized
regression coefficients
⢠Perform some Diagnostics
106
107. Regression Diagnostics
⢠Unusual and Influential data (Outliers/Leverage)
⢠Tests on Normality of Residuals
⢠Tests on Nonconstant Error of Variance
(Heteroscedasticity)
⢠Tests on Correlations among Predictors
(Multicollinearity)
⢠Tests on Nonlinearity
⢠Tests on Dependence of Residuals
(Autocorrelation)
⢠Model Specification
107
108. Diagnostics: Collinearity Analysis
⢠This option requests a detailed analysis of
collinearity among the regressors. This includes
eigenvalues, condition indices, and
decomposition of the variances of the estimates
with respect to each eigenvalue.
108
109. Diagnostics: Collinearity Analysis
⢠Check Tolerance (1/VIF) or Variance Inflation (VIF)
⢠Some researchers use the more lenient cutoff of 5.0 or even
10.0 to signal when multicollinearity is a problem. The
researcher may wish to drop the variable with the highest VIF
if multicollinearity is indicated and theory warrants.
⢠The condition indices are the square roots of the ratio of the
largest eigenvalue to each individual eigenvalue. The largest
condition index is the condition number of the
scaled X matrix. Belsey, Kuh, and Welsch (1980) suggest that,
when this number is around 10, weak dependencies might be
starting to affect the regression estimates. When this number
is larger than 100, the estimates might have a fair amount of
numerical error (although the statistical standard error almost
always is much greater than the numerical error).
109
110. Diagnostics: Heteroscedasticity Test
⢠This option tests that the first and second
moments of the model are correctly specified.
⢠Asymptotic covariance matrix. This option
displays the estimated asymptotic covariance
matrix of the estimates under the hypothesis of
heteroscedasticity.
110
111. Diagnostics: Durbin-Watson Statistic
⢠The Durbin-Watson statistic shows whether or not the
errors have first-order autocorrelation. (This test is
appropriate only for time series data.) The sample
autocorrelation of the residuals is also produced.
⢠The value of d ranges from 0 to 4. Values close to 0
indicate extreme positive autocorrelation; close to 4
indicates extreme negative autocorrelation; and close to
2 indicates no serial autocorrelation. As a rule of thumb,
d should be between 1.5 and 2.5 to indicate
independence of observations. Positive autocorrelation
means standard errors of the b coefficients are too small.
Negative autocorrelation means standard errors are too
large.
111
112. ⢠Under Plots, select Custom list of plots under Show plots
for regression analysis. In the menu that appears, uncheck
the box for Diagnostic plots and check the box for
Histogram plot of the residual, Normal quartile
plot of the residual and Residual plots.
112
113. Regression Analysis
113
These are the F Value and
p-value, respectively,
testing the null hypothesis
that the Model does not
explain the variance of
the response variable.
These are the F Value and
p-value, respectively,
testing the null hypothesis
that the Model does not
explain the variance of
the response variable.
R-Square defines the
proportion of the total
variance explained by
the Model.
R-Square defines the
proportion of the total
variance explained by
the Model.
114. Regression Analysis
114
These are the t Value and
p-value, respectively,
testing the null hypothesis
that the coefficients are
significantly equal to 0.
These are the t Value and
p-value, respectively,
testing the null hypothesis
that the coefficients are
significantly equal to 0.