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What is SAS? What are the functions does it performs?
SAS is an integrated set of software products. The acronym stands for Statistical Analysis System.
- Information retrieval and data management
- Writing reports and graphics
- Statistical analysis, econometrics and data mining
- Business planning, forecasting and decision support
- Operation research and Project management
- Quality Improvement
- Data Warehousing
- Application Development
What is the basic structure of SAS Programming?
The basic structure of SAS are
- Program Editor
- Explorer Window
- Log Window
What is the basic syntax style in SAS?
To run program successfully, and you have following basic elements:
- There should be a semi-colon at the end of every line
- A data statement that defines your data set
- Input statement
- There should be at least one space between each word and statement
- A run statement
What are SAS/Access and SAS/Connect?
SAS/Access only process through the database like oracles, SQL-server, Ms-Access etc. SAS/Connect only use server connections.
What is the Difference between SCAN and SUBSTR?
SCAN extracts words within a value that is marked by delimiters. SUBSTR extracts a portion of the value by stating the specific location. It is best used when we know the exact position of the sub string to extract from a character value.
What is Data Step?
The Data step creates an SAS dataset which carries the data along with a “data dictionary.” The data dictionary holds the information about the variables and their properties.
What is DATA _NULL_?
The DATA _NULL_ is mainly used to create macro variables. It can also be used to write output without creating a dataset. The idea of “null” here is that we have a data step that actually doesn’t create a data set.
What is PDV?
The logical area in the memory is represented by PDV or Program Data Vector. At the time, SAS creates a database of one observation at a time. An input buffer is created at the time of compilation which holds a record from an external file. The PDV is created following the input buffer creation.
What do the put and input function do?
Input function converts character data values to numeric values. Put function converts numeric values to character values.
Ex: for input: input (source, informat)
What are the data types does SAS Contain?
The data types in SAS are Numeric and Character.
What are the special input delimiters?
The input delimiters are DLM and DSD
What is the purpose of using the N=PS option?
The N=Ps option creates a buffer in memory which is large enough to store PS lines and enables a page to be formatted randomly prior to it being printed.
What is the difference between NODUPKEY and NODUP options?
The difference between the NODUP and NODUPKEY is that, NODUP compares all the variables in our dataset while NODUPKEY compares just the BY variables.
Mention the validation tools used in SAS?
For Data Set: Data set name/ debug Data set: Name/stmtchk
For Macros: Options: mprint mlogic symbolgen
Explain what does PROC print, and PROC contents are used for?
To display the contents of the SAS dataset PROC print is used and also to assure that the data were read into SAS correctly. While, PROC CONTENTS display information about an SAS dataset.
Explain what is the use of function Proc summary?
The syntax of proc summary is same as that of proc means, it computes descriptive statistics on numeric variables in the SAS dataset.
What difference did you find among version 6, 8 and 9?
Architecture is fundamentally different from any prior version of SAS. In the SAS 9 architecture, SAS relies on a new component, the metadata server, to provide an information layer between the programs and the data they access. Metadata, such as security permission for SAs libraries and where the various SAs servers are running, are maintained in a common repository.
Explain what Proc glm does?
Proc glm performs simple and multiple regression, analysis of variance (ANOVAL), analysis of covariance, multivariate analysis of variance and repeated measure analysis of variance.
Explain what is SAS informats?
SAS INFORMATS are used to read, or input data from external files known as Flat Files ASCII files, text files or sequential files. The informat will tell SAS on how to read data into SAS variables.
Mention the category in which SAS Informats are placed?
SAS informats are placed in three categories,
- Character Informats: $INFORMATw
- Numeric Informats: INFORMAT w.d
- Date/Time Informats: INFORMAT w.
What function CATX syntax does?
CATX syntax concatenate character strings remove trailing and leading blanks and inserts separators.
Explain what is the use of PROC gplot?
PROC gplot has more options and can create more colorful and fancier graphics.