topic Re: Base SAS certification exam question in SAS Procedures

Base SAS certification exam question

GavyK — Sun, 04 Aug 2013 02:26:23 GMT

Hi, Could anyone help me understand the logic behind the following question, before giving me the answer?

Given the SAS data set WORK.INPUT:

Var1     Var2

 A        one

A        two

 B        three

 C        four

 A        five

The following SAS program is submitted:

data WORK.ONE WORK.TWO;

set WORK.INPUT;

if Var1='A' then output WORK.ONE;

output;

 run;

How many observations will be in data set WORK.ONE?

Re: Base SAS certification exam question

PGStats — Sun, 04 Aug 2013 02:59:59 GMT

The DATA statement announces that two datasets will be produced in the WORK library : ONE and TWO.

the OUTPUT WORK.ONE statement outputs Var1 and Var2 to dataset ONE, but only when Var1='A'

the OUTPUT statement outputs Var1 and Var2 to both datasets, whatever the value of Var1.

...

Do the counting

Re: Base SAS certification exam question

Cynthia_sas — Sun, 04 Aug 2013 17:55:53 GMT

Hi:

I agree with PGStats... do the counting...or write the program and run the program. Equally important for understanding how the logic works, after you figure out how many obs are in WORK.ONE, try to figure out how many obs will be in WORK.TWO, then try to figure out WHY the counts are different. As a help, here's the code that makes the dataset WORK.INPUT.

Then you should be able to code and test the rest.

cynthia

data work.input;

infile datalines;

input var1 $ var2 $;

return;

datalines;

A one

A two

B three

C four

A five

;

run;

Re: Base SAS certification exam question

GavyK — Sun, 04 Aug 2013 21:36:47 GMT

Thanks, PGStats & Cynthia.

Here's another one:

The following SAS program is submitted:

data gt100;

set airplanes(keep = type mpg load);

load = mpg * 150;

run;

The program fails to execute due to syntax errors.

What is the cause of the syntax error?

A. MPG is not a numeric variable.

B. LOAD is not a variable in the data set GT100.

C. LOAD is not variable in the data set AIRPLANES.

D. LOAD must be defined prior to the SET statement.

Thanks in advance,

Re: Base SAS certification exam question

GavyK — Sun, 04 Aug 2013 21:47:03 GMT

Cynthia,

I am not sure if the code that you've given above would yield the same results as the code given in my original post.

My question says ' how many observations will be data set WORK.ONE? And if I run the count(as suggested by PGStats) then it is 8 observations of Var A that would go into WORK.ONE.

On the other hand,I did run the code that you gave, and what the DATALINES statement did was simply produced the same results as given in the code and total number of observation that the LOG gave were 5. So different results! thanks , anyways!

Gavy

Re: Base SAS certification exam question

Cynthia_sas — Sun, 04 Aug 2013 21:55:11 GMT

Gary:

My program will ONLY create WORK.INPUT. You would have needed to type in the *REST* of the program yourself. I said I was going to get you started. Clearly, since you already cut and pasted the question part of the program (with work.one and work.two), I didn't think I needed to retype that portion.

So you are correct, that WORK.INPUT has 5 observations. That is "given" in the statement of the problem. If you had typed and run the *REST* of the program you would have been able to verify your counting, as shown in the attached log, that WORK.ONE has 8 obs and WORK.TWO has 5 obs. WORK.ONE has the "extra" obs because of the "extra" output in the IF statement.

cynthia

Re: Base SAS certification exam question

Cynthia_sas — Sun, 04 Aug 2013 21:56:34 GMT

Hi:

Nobody from the forum is going to be in the exam with you. Does the test question show you what variables are in WORK.AIRPLANES? You should be able to figure this one out, too.

cynthia

Re: Base SAS certification exam question

GavyK — Sun, 04 Aug 2013 22:07:07 GMT

Cynthia,

I am cracking a list of sample questions and cross-checking reliability of solutions given on the website. I have my answers with me but some of the online answers seem to be wrong.

Thanks

Re: Base SAS certification exam question

Cynthia_sas — Mon, 05 Aug 2013 03:29:12 GMT

Hi,

IF (and it 's a big IF) any of the questions were wrong, they would be corrected immediately. But I am not aware of any of the sample questions being wrong. If you think the answer to a question is wrong, then write and run a program that shows it is wrong. You can send your program code and your log to certification@sas.com to report a possible problem with the question/answer.

I think it is safe to assume that the posted answers are correct. If you think an answer is wrong, then you need to figure out WHY or HOW the posted answer could be right and what about your approach led you to a different answer.

cynthia

Re: Base SAS certification exam question

JVarghese — Mon, 14 Apr 2014 20:16:18 GMT

If you have no information as to what variables are there in work.airplanes, the most probable answer can be option C I guess. Because, The keep= option tries to access load variable to be used in later statements since it happened to be in SET statement. So, if load variable is not already defined in the airplanes dataset, the program would stop during execution.

Re: Base SAS certification exam question

Vikesh — Sun, 01 Jun 2014 14:56:33 GMT

It would write 8 obs in work.one dataset.

First output statement would write 3 obs (where var1 =''A' and second output statement would write each of the obs's to both the output datasets.

thus total obs written to work.one dataset = 3+5 =8

Re: Base SAS certification exam question

KakaDa — Thu, 26 Jun 2014 07:10:33 GMT

Re: Base SAS certification exam question

SujataHiremath — Fri, 04 Jul 2014 06:36:28 GMT

Answer is 8.

When assigned as OUTPUT in this program both in ONE & TWO include whatever data set is in INPUT. So both will be included 5 observations.

After running IF statement it includes 3 more observations to ONE as per the condition, So ONE contain 8 observation.

If you execute without OUTPUT then answer will be 3.

Re: Base SAS certification exam question

bustergomez — Mon, 14 Jul 2014 19:44:29 GMT

Hi,

would anyone, I was curious about the question. I think if the code had an 'else if' instead of just output then the code would separate the dataset, as I would presume this is what you would want to do 'normally'.

data work.one work.two;

set work.input;

if var1='A' then output work.one;

else output work.Two;

run;

my question would would there be a case that some one would use the original program?

marv

Re: Base SAS certification exam question

Cynthia_sas — Wed, 16 Jul 2014 00:32:30 GMT

Hi:

That is one possible scenario, if the goal is to split the data based on the value of VAR1 so that ONLY the observations with VAR1=A are placed in WORK.ONE and the other obs are placed in WORK.TWO.

However, the point of the question was not for the student to rewrite the question or recast it into a different question. The question gives the code. No matter how improbably you think the example is, the question has a point that is based on how SAS Syntax works. The question, based on the way the code was originally written, asks the student to figure out how many observations would be in WORK.ONE. The correct answer was 8. The question is designed to test whether the student understands how the explicit OUTPUT statement works. A frequent beginner mistake is failing to code the ELSE because they do NOT understand how the explicit OUTPUT statement works. And the consequences of not understanding how the explicit OUTPUT statement works is to get the "unexpected" number of observations in one or more than one of the output datasets. If you understand HOW the explicit OUTPUT statements works, then you will understand WHY the correct answer is 8, and so, you will always be able to answer a question like this correctly. The fact you understand that a well placed ELSE might help you out in this instance is great, but on the exam, you have to answer the question you are asked.

cynthia

Re: Base SAS certification exam question

bustergomez — Wed, 16 Jul 2014 01:35:00 GMT

Thanks Cynthia,

Makes sense, I've been studying for SAS certification and I agree, many of the question are the way you described. It's extremely helpful just studying the material in this way as I get tons of 'Ah, that's how that works' moments when I encounter code that otherwise would not make sense.

Also just wanted to say Cynthia you do a great job answering all of our SAS questions, you must be on your millionth question!

I don't know how you do it.

Marv

Re: Base SAS certification exam question

Tom — Wed, 16 Jul 2014 03:50:59 GMT

Looks like these questions are like those on most standardized tests, you should pick the BEST answer. Using the Sherlock Holmes method helps (if you eliminate the impossible ...)

That is don't get too nit-picky.

In this case you can eliminate three of the answers as being clearly wrong.

A Would just cause SAS to automatically convert characters values to numeric values.

B Is just nonsense because this data step is defining the data set GT100.

D Is very poorly worded as what do they mean by defining LOAD in the context of this simple data step? The most normal meaning is say that they mean you should have defined it via a LENGTH or ATTRIB statement before referencing it in the KEEP= option of the SET statement? But no matter how you interpret the meaning of this choice SAS does NOT require you to pre-define variables.

So you are left with C as the BEST answer. That one is only wrong if you know that the option DKRICOND is set to WARN instead of ERROR.

Re: Base SAS certification exam question

SujataHiremath — Thu, 17 Jul 2014 06:17:20 GMT

Hi,

Right now you got resolved current question but actual question in SAS BASE CERTIFICATION will be more tougher. Actually A00-201 series dumps will available but examination will series A00-211. Don't get confused. After better preparation only go for examination.

Sujata

Re: Base SAS certification exam question

himzi_SAS — Sat, 01 Nov 2014 10:41:19 GMT

Hi Cynthia,

I have been following your explanations and it helped me a lot. I am going to write my SAS base exam very soon but have some doubts. So if you can clear one of them that would help me a lot. see the following question:

data allobs;

set sasdata.banks;

capitaI=0;

do year = 2000 to 2020 by 5;

capital + ((capital+2000) * rate);

output;

end;

run;

How many observations will the ALLOBS data set contain?

A. 5

B. 15

C. 20

D. 25

I know the answer but want to know the exact explanation.

Thanks,

Re: Base SAS certification exam question

Tom — Sat, 01 Nov 2014 14:18:57 GMT

You did not provide enough information to answer the question. How many observations are in the input data set?