topic Re: Problem with prep question in SAS Programming

Problem with prep question

papertrail — Thu, 15 Dec 2016 10:33:30 GMT

Hi, I'm preparing for my Base Programming Exam and I'm stuck with one question from the Pass4Sure catalogue. The explanation doesn't really help:

The right answer is A. While I do understand why A doesn't produce a missing value in the last observation, I don't get why any of the other options should. I've pondered over this one for a while now but I'm not getting further. Especially option D should effectively do the same as A in my opinion.

I would appreciate your help!

Re: Problem with prep question

Kurt_Bremser — Thu, 15 Dec 2016 10:42:22 GMT

options B and D use a simple totquantity + quantity calculation; they cause no automatic retain, always reference a missing value (totquantity), therefore the result will be missing.

option C is a simple syntax error.

Re: Problem with prep question

gamotte — Thu, 15 Dec 2016 10:43:55 GMT

Answer D uses the "+" operator which produces a missing value if one of the operands is missing.
The 0 in the retain statement only provides an initialization which is overwritten by the operation.

Re: Problem with prep question

papertrail — Thu, 15 Dec 2016 10:44:14 GMT

Now I get it, thanks a lot!