The SAS System, originally
Statistical Analysis System, is an integrated system of software
products provided by the SAS Institute that enables a user to perform:
• Data entry, retrieval,
management, and mining
• Report writing and graphics
• Statistical Analysis and Operations Research
• Forecasting and Decision Support
• Data Warehousing (Extract, Transform, Load)
Though SAS system provides
a menu driven interface, most of the interaction with SAS system in
analytics is done through writing SAS programs. SAS programs provide
high level of flexibility to the user. Also, platforms like Unix and
Mainframe do not provide a menu driven interface for SAS.
A SAS program is composed
of two fundamental components:
DATA step(s)- the part of
the program in which a structure for the data to be analyzed is
created. Variables corresponding to the various elements of the data
set are defined, and the data are assigned to the Variables. Data may
be input manually in the body of the program, or they may be read in
from a file. Additionally data may be stored in a data warehouse (for
example Consumer Data Warehouse in Stoner server).
PROCs (PROCedures) - the
SAS language is organized into a series of procedures, or PROCs, each
of which is dedicated to a particular form of data manipulation or
statistical analysis to be performed on data sets created in the DATA
step. For example:
PROC PRINT: Prints the
contents of a data set and create reports.
PROC FREQ: Produces frequency and cross tabulation tables on the
variables specified.
PROC MEANS: Computes means, standard deviations and other summary
Statistics.
PROC TTEST: Computes the 2-sample t-test for comparing the means of 2
treatments.
PROC REG: Performs regression analysis using the method of least
squares.
PROC GPLOT: Constructs plots of the data as specified by the user.
A SAS program consists of
one or more DATA steps to get the data into a format that SAS can
understand and one or more calls to PROCs to perform various analyses
on the data.
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