Conflicting info on rounding answers FE in the exam

[HiThere]

I'm taking an FE exam prep class, and the instructor has made what I think is a significant (and possibly inaccurate) statement: He has stated that you should always round your answers up on the exam, if the exact answer is not given as a choice, or if materials such as the charts in the economics section of the handbook don't given an exact number.

Now, I wouldn't have any problem with that, if:

1. I could find any confirmation at all from any other source that such practice is expected on the exam.

2. Nearly 50% of all questions on the exam end with "is nearest to: (A, B, C, or D)"

3. The instructor was consistent in his rounding practice with answers given in the book. He is not: On at least one out of twenty questions we reviewed the other night, he made the assertion that the practice problem answer in the book/key he was using was wrong due to a rounding error where he rounded up and the authors did not...the exact answer given by the formula used was closer to the answer the authors chose.

4. The instructor was consistent with himself: He has provided several seemingly arbitrary rules for when to "always" round up and when the rule doesn't apply, and may little attempt to clarify.

Anyway, I think this is all bunk, and before I drive myself crazy I wanted to get you guys'/gals' take on the matter. In my mind, if the question ends with "is closest to: (A, B, C, or D)", then I'm going to round to the nearest value in the possible answers given, unless the problem is illustrating some case where you would logically round up (such as selecting a piece of equipment from a set with given specific tolerances, given an expected operational extreme).

 

[roadwreck]

it's been a while since I took the FE, but I recall no directive to "always round your answer up". I would pick the answer which most closely matches what I calculated. It's usually pretty obvious, I can't recall an instance where two possible answers were so close to one another (and the answer I calculated) where it wasn't obvious which one I should pick.

That said, I think they do provide answers that match common mistakes people make in there calculations, so just b/c you come up with an answer that matches with one of the possible answers doesn't mean you are right.

 

[benbo]

I'm taking an FE exam prep class, and the instructor has made what I think is a significant (and possibly inaccurate) statement: He has stated that you should always round your answers up on the exam, if the exact answer is not given as a choice, or if materials such as the charts in the economics section of the handbook don't given an exact number.

I think what he means is that when you're considering things like stress or capacity you should always pick an answer that is greater than the maximum capacity you need. But after that you should pick the closest answer. For example, if they ask you for a circuit breaker needed to protect a certain current, you want to make sure you pick an answer above that current. After that, pick the closest answer.

 

[Dexman PE]

Along the same lines as benbo's response: If you need to round, do so on the conservative side. If you get 15.5 and your choices are 15 and 16, pick the conservative side. If you're dealing with circuit breakers and current like in benbos response above you'd get 16, but if it's how many loads of material you can receive in 1 hour (like dump trucks to a construction site), you'd get 15.

Either case, I would not recommend rounding until you get to your final answer. If you do round anything, round your numbers to match the significant digits of the numbers you're using for your calcs. (like 12.2/5.6 =2.17857... should be rounded to 2.18)