Significant figures

[bec]

Can anyone give me a rundown?

I thought that we were supposed to do all our calculations using an 'extra' sig fig, then round down at the end...but it seems like VCAA doesn't agree (i've done a couple of past exam Qs and i often get them wrong by .1 or .2 because I've rounded at a different place)

So, what's the deal? Are we supposed to do all our calculations with the number of significant figures we want to end up with?

[iamdan08]

Your answer has to have the same number of significant figures as your least accurate number i.e the number with the lowest number of sig figs.

You also have to keep the large numbers from your calculations right to the end, and then correct your final answer to the right number of significant figures. (correct me if i'm wrong) 

[bec]

You also have to keep the large numbers from your calculations right to the end, and then correct your final answer to the right number of significant figures. (correct me if i'm wrong) 

That's what I thought too - but check out the assesment reports from the vcaa site, they don't always do that...

[iamdan08]

Yeah your right, it seems as though every calculation they do they are using the right amount of sig figs. Not doing it at the end which is what i thought you were supposed to do!

[Mao]

Yeah your right, it seems as though every calculation they do they are using the right amount of sig figs. Not doing it at the end which is what i thought you were supposed to do!

uh really?

I thought otherwise too =\

would they go all harsh taking points off for 0.1 or 0.2 off when we're using the right method??

[iamdan08]

I hope not! But you never know with those tight ass VCAA markers!

[Four]

My Methods teacher told me that when he was a VCAA examiner a few years ago, one question which specified that 'answers were to be given to 1 decimal place' had an answer that was exactly a whole number. VCAA specifically told its examiners to mark down anyone who omitted the redundant decimal place (ie; anyone who wrote 5 instead of 5.0), but my teacher awarded the marks regardless.

I guess it sometimes comes to the individual examiner’s judgement, rather than VCAA’s.

[Collin Li]

My Methods teacher told me that when he was a VCAA examiner a few years ago, one question which specified that 'answers were to be given to 1 decimal place' had an answer that was exactly a whole number. VCAA specifically told its examiners to mark down anyone who omitted the redundant decimal place (ie; anyone who wrote 5 instead of 5.0), but my teacher awarded the marks regardless.

I guess it sometimes comes to the individual examiner’s judgement, rather than VCAA’s.

Yeah, I didn't lose a mark when I stated "0" instead of "0.0" for a question similar to this (2006 Exam 2).

I always carry my calculations all the way through. I neglected that on a recent exam I did, so hopefully my answers are not too far off.