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Q&A Session for SAS Global Certification Webinar Series: Managing Data

by Community Manager 4 weeks ago - edited 4 weeks ago (882 Views)

Questions about Webinar Logistics

Q: How can I access today's presentation material as well as the two previous webinars? ­

A: ­You can get access the material from today as well as the previous webinars by going to: communities.sas.com > Find a Community > Learn SAS > SAS Certification. Here’s the direct link: https://communities.sas.com/t5/SAS-Certification/bd-p/certification.


Questions about the SAS Certification Program

Q: How often can one take the test? What is the procedure?

A: You can sign up for the exam at the following website: http://www.pearsonvue.com/sas/  Per the policy, "Candidates may attempt each certification exam up to five time in a 12-month period, waiting a minimum of 14 days between attempts.  Exam charges are incurred for each exam attempt. Exams that do not comply with this retake policy will be considered invalid and will not be eligible for a refund and/or a certification credential. Once a passing score is achieved on a specific exam, no further attempts are allowed on that exam.” You can find more certification general FAQ at: https://www.sas.com/en_us/certification/faq.html


Q: How many months of hands on SAS experience will be helpful to pass the exam to get certification?

A: In general, six months to a year of experience using the content area material is recommended.


Q: ­Is there an exam for specific to Mainframe SAS?­

A: ­No, SAS code is pretty much the same for all operating systems. The small percentage of code that must change according to the specific operating system is not asked on the certification exam. The exam sticks to SAS code that is operating system independent.


Q: Do the SAS Programming 1 and 2 classes cover 100% of the material on the base exam or do you need to go through any other materials?

A: The current SAS Programming 1 and 2 courses cover the majority of topics within the five content areas.

Questions about the Managing Data Content Area


Q: ­What is the difference between 'by' and 'key' in PROC SORT step?­

A: ­The BY variable is used when you need to sort BY a specific variable.  We often call the variable that is listed first the KEY variable.  If you are thinking that PROC SORT is capable of creating an index, then that would not be correct. 


Q: ­Can you explain Question 4 again?

A: ­There are only 3 variables created in that DATA step. AGE (numeric) is created with the first assignment statement. GENDER (character) is created with the second assignment statement and it is overwritten with the uppercase value in the fourth assignment statement. HIRED (numeric) is created in the third assignment statement.


Q: ­Do we need to remember all the common SAS formats before we take the exam?­

A: The common formats on slide 23 are all good formats to know for the exam.  You can get a list of Formats by Category here: http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a001263753.htm 


Q: Is the LENGTH statement assigned at compile time before any data is read in with the SET statement at execution time?

A: ­Yes, that is correct! The length is set during compilation. The length is typically determined from the first place SAS sees the variable in the step.


Q: ­What is the $ syntax doing on the statement?­

A: ­The $ when used in SAS indicates a character variable. So if you see a $ in a length statement:  length name $ 25;  it means the variable name is a character variable with a length of 25 bytes.­ If you see it in an array statement for example here: array yr(2) $  ('Yes','No'); it means we are creating a character array and in the end, we will create two character variables, yr1 and yr2. Yr1 value will be Yes, and yr2 value will be No.


Q: For Question 7, what is the difference between the output from A and B?

A: ­ The output for A shows only variable names. The label for NAME is not visible. The output for B shows the label for the NAME variable, Student. Even though there is a LABEL statement in the DATA step, the label(s) will not show up in the output if you do not use the LABEL option on your PROC PRINT statement.  You must use the LABEL option in PROC PRINT for the labels to appear in the results. 


Q: What is the difference between the CATT and CATX functions?­

A: ­CATT will concatenate character strings and remove trailing blanks. CATX will concatenate character strings and remove leading and trailing blanks plus the first argument specifies a character string that is used as a delimiter between concatenated items.


Q: ­How many variables will be created with the following statement? array test(3) _temporary_; ­

A: When you use the keyword _TEMPORARY_ in place of variable names in your array definition statement, no variables are created. This statement creates three spots in the Program Data Vector but they are not considered variables that you can reference with a variable name.


Q: ­Can you please explain a little more on byte size?­

A: Byte size is the storage for SAS variables. Character variables are stored 1 byte per character, and have a maximum of 32,767 characters, which is equivalent to 32,767 bytes. Numeric variables are stored in 8 bytes floating point representation, which can have up to 16 or 17 significant digits.


Q: ­The array example showed the array name followed by the number of elements in parentheses and brackets, why both?­

A: You can enclose the subscript in braces ({}), brackets ( [ ] ) or parentheses (( )). The braces, brackets, or parentheses are interchangeable for the subscript, your choice.


Q: Can you explain ­the first. and last. variables?

A: When you us a BY statement in the DATA step, SAS creates two temporary variables FIRT.BY-variable and LAST.BY-variable for each variable on the BY statement.  The First. variable has a value of 1 for the first observation in a BY group. Otherwise, it equals 0. The Last. variable has a value of 1 for the last observation in a BY group. Otherwise, it equals 0.



data new;  
   set old;
   by id;

first. and last. variables example.jpg


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