When answering this question, discuss the general meaning of the date and how it impacts SAS operations. Employers ask this question to determine if candidates understand database date values in general and in reference to SAS in particular. (Note: If there are few repeated characters, a data set can occupy more space in compressed form than in uncompressed form, due to the higher overhead per observation.) For more details on SAS compression see “SAS Language: Reference, Version 6, First Edition, Cary, NC: SAS Institute Inc., 1990”. This beginner-level question helps employers identify which candidates know the basics of the SAS system. The CPU time required to prepare compressed observations for input/output observations is increased because of the overhead of compressing and expanding the observations. The disadvantages include not being able to use SAS observation number to access an observation. The advantages of using a SAS compressed data set are reduced storage requirements for the data set and fewer input/output operations necessary to read from and write to the data set during processing. To create a compressed SAS data set, use the COMPRESS=YES option as an output DATA set option or in an OPTIONS statement.Compressing a data set reduces its size by reducing repeated consecutive characters or numbers to 2-bye or 3-byte representations.To uncompress observations, you must use a DATA step to copy the data set and use option COMPRESS=NO for the new data set. A pharmacokinetic study might use SAS/ETS software’s features for nonlinear systems to model the dynamics of drug metabolism in different tissues.
SAS/ETS software is useful whenever time dependencies, simultaneous relationships, or dynamic processes complicate data analysis.For example, an environmental quality study might use SAS/ETS software’s time series analysis tools to analyze pollution emissions data. The common theme relating the many applications of the software is time series data: SAS/ETS software is useful whenever it is necessary to analyze or predict processes that take place over time or to analyze models that involve simultaneous relationships.Īlthough SAS/ETS software is most closely associated with business, finance and economics, time series data also arise in many other fields. Major uses of SAS/ETS procedures are economic analysis, forecasting, economic and financial modeling, time series analysis, financial reporting, and manipulation of time series data. SAS/ETS software provides tools for a wide variety of applications in business, government, and academia.