SAS认证220道练习题及详细答案(可编辑).doc

SAS认证220道练习题及详细答案 SAS Certificate Base Practice Questions and Detailed Answers Chapter 1 Basic Concepts Chapter 2 Referencing Files and Setting Options Chapter 3 Editing and Debugging SAS Programs Chapter 4 Creating List Reports Chapter 5 Creating SAS Data Sets from Raw Data Chapter 6 Understanding DATA Step Processing Chapter 7 Creating and Applying User-Defined Formats Chapter 8 Creating Enhanced List and Summary Reports Chapter 9 Producing Descriptive Statistics Chapter 10 Producing 6>HTML Output Chapter 11 Creating and Managing Variables Chapter 12 Reading SAS Data Sets Chapter 13 Combining SAS Data Sets Chapter 14 Transforming Data with SAS Functions Chapter 15 Generating Data with DO Loops Chapter 16 Processing Variables with Arrays Chapter 17 Reading Raw Data in Fixed Fields Chapter 18 Reading Free-Format Data Chapter 19 Reading Date and Time Values Chapter 20 Creating a Single Observation from Multiple Records Chapter 21 Creating Multiple Observations from a Single Record Chapter 22 Reading Hierarchical Files 1 Chapter 1 Basic Concepts Answer Key 1 How many observations and variables does the data set below contain a 3 observations 4 variables b 3 observations 3 variables c 4 observations 3 variables d cant tell because some values are missing Correct c answer Rows in the data set are called observations and columns are called variables Missing values dont affect the structure of the data set 2 How many program steps are executed when the program below is processed data usertables infile jobs input date name job run proc sort data usertables by name run proc print data usertables run a three b four c five d six Correct a answer When it encounters a DATA PROC or RUN statement SAS stops reading statements and 2 executes the previous step in the program The program above contains one DATA step and two PROC steps for a total of three program steps 3 What type of variable is the variable AcctNum in the data set below a numeric b character c can be either character or numeric d cant tell from the data shown Correct b answer It must be a character variable because the values contain letters and underscores which are not valid characters for numeric values 4 What type of variable is the variable Wear in the data set below a numeric b character c can be either character or numeric d cant tell from the data shown Correct a answer It must be a numeric variable because the missing value is indicated by a period rather than by a blank 3 5 Which of the following variable names is valid a 4BirthDate b Cost c _Items_ d Tax-Rate Correct c answer Variable names follow the same rules as SAS data set names They can be 1 to 32 characters long must begin with a letter AZ either uppercase or lowercase or an underscore and can continue with any combination of numbers letters or underscores 6 Which of the following files is a permanent SAS file a SashelpPrdSale b SasuserMySales c ProfitsQuarter1 d all of the above Correct d answer To store a file permanently in a SAS data library you assign it a libref other than the default Work For example by assigning the libref Profits to a SAS data library you specify that files within the library are to be stored until you delete them Therefore SAS files in the Sashelp and Sasuser libraries are permanent files 7 In a DATA step how can you reference a temporary SAS data set named Forecast a Forecast b WorkForecast c SalesForecast after assigning the libref Sales d only a and b above Correct d answer To reference a temporary SAS file in a DATA step or PROC step you can specify the one- 4 level name of the file for example Forecast or the two-level name using the libref Work for example WorkForecast 8 What is the default length for the numeric variable Balance a 5 b 6 c 7 d 8 Correct d answer The numeric variable Balance has a default length of 8 Numeric values no matter how many digits they contain are stored in 8 bytes of storage unless you specify a different length 9 How many statements does the following SAS program contain proc print data newprodsale label double var state day price1 price2 where state NC label state Name of State run a three b four c five d six Correct c answer The five statements are PROC PRINT statement two lines long 5 VAR statement WHERE statement on the same line as the VAR statement LABEL statement RUN statement on the same line as the LABEL statement 10 What is a SAS data library a a collection of SAS files such as SAS data sets and catalogs b in some operating environments a physical collection of SAS files c in some operating environments a logically related collection of SAS files d all of the above Correct d answer Every SAS file is stored in a SAS data library which is a collection of SAS files such as SAS data sets and catalogs In some operating environments a SAS data library is a physical collection of files In others the files are only logically related In the Windows and UNIX environments a SAS data library is typically a group of SAS files in the same folder or directory Chapter 2 Referencing Files and Setting Options 1 If you submit the following program how does the output look options pagesize 55 nonumber proc tabulate data clinicadmit class actlevel var age height weight table actlevel age height weight mean 6 run options linesize 80 proc means data clinicheart min dec 1 var arterial heart cardiac urinary class survive sex run a The PROC MEANS output has a print line width of 80 characters but the PROC TABULATE output has no print line width b The PROC TABULATE output has no page numbers but the PROC MEANS output has page numbers c Each page of output from both PROC steps is 55 lines long and has no page numbers and the PROC MEANS output has a print line width of 80 characters d The date does not appear on output from either PROC step Correct c answer When you specify a system option it remains in effect until you change the option or end your SAS session so both PROC steps generate output that is printed 55 lines per page with no page numbers If you dont specify a system option SAS uses the default value for that system option 2 In order for the date values 05May1955 and 04Mar2046 to be read correctly what value must the YEARCUTOFF option have a a value between 1947 and 1954 inclusive b 1955 or higher c 1946 or higher d any value Correct d answer As long as you specify an informat with the correct field width for reading the entire date value the YEARCUTOFF option doesnt affect date values that have four-digit years 3 When you specify an engine for a library you are always specifying a the file format for files that are stored in the library 7 b the version of SAS that you are using c access to other software vendors files d instructions for creating temporary SAS files Correct a answer A SAS engine is a set of internal instructions that SAS uses for writing to and reading from files in a SAS library Each engine specifies the file format for files that are stored in the library which in turn enables SAS to access files with a particular format Some engines access SAS files and other engines support access to other vendors files 4 Which statement prints a summary of all the files stored in the library named Area51 a proc contents data area51_all_ nods b proc contents data area51 _all_ nods c proc contents data area51 _all_ noobs d proc contents data area51 _all_nods Correct a answer To print a summary of library contents with the CONTENTS procedure use a period to append the _ALL_ option to the libref Adding the NODS option suppresses detailed information about the files 5 The following PROC PRINT output was created immediately after PROC TABULATE output Which SAS system options were specified when the report was created 8 a OBS DATE and NONUMBER b PAGENO 1 and DATE c NUMBER and DATE only d none of the above Correct b answer Clearly the DATE and PAGENO options are specified Because the page number on the output is 1 even though PROC TABULATE output was just produced If you dont specify PAGENO all output in the Output window is numbered sequentially throughout your SAS session 6 Which of the following programs correctly references a SAS data set named SalesAnalysis that is stored in a permanent SAS library a data saleslibrarysalesanalysis set mydataquarter1sales if sales 100000 run b data mysalestotals set sales_99salesanalysis if totalsales 50000 run c proc print data salesanalysisquarter1 var sales salesrep month run d proc freq data 1999datasalesanalysis 9 tables quartersales run Correct b answer Librefs must be 1 to 8 characters long must begin with a letter or underscore and can contain only letters numbers or underscores After you assign a libref you specify it as the first element in the two-level name for a SAS file 7 Which time span is used to interpret two-digit year values if the YEARCUTOFF option is set to 1950 a 1950-2049 b 1950-2050 c 1949-2050 d 1950-2000 Correct a answer The YEARCUTOFF option specifies which 100-year span is used to interpret two-digit year values The default value of YEARCUTOFF is 1920 However you can override the default and change the value of YEARCUTOFF to the first year of another 100-year span If you specify YEARCUTOFF 1950 then the 100-year span will be from 1950 to 2049 8 Asssuming you are using SAS code and not special SAS windows which one of the following statements is false a LIBNAME statements can be stored with a SAS program to reference the SAS library automatically when you submit the program b When you delete a libref SAS no longer has access to the files in the library However the contents of the library still exist on your operating system c Librefs can last from one SAS session to another d You can access files that were created with other vendors software by submitting a LIBNAME statement Correct c answer The LIBNAME statement is global which means that librefs remain in effect until you modify them canc