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AQA being awkward

Hi, so basically I'm having trouble getting a straight answer with this: how do we find the uncertainty in a gradient using the worst lines (i.e lines passing through the error bars giving the greatest and least possible gradients). I've read in the textbook (cgp) that the uncertainty is simply the range of the worst gradients. However, on the markscheme for last years paper 3 section A, the correct method was to find the range and half it. And to make it more confusing another markscheme says it is just the range. So which is right? Range or range/2?
Reply 1
It is plus or minus half the range
Original post by Ladkus
It is plus or minus half the range


So would you say the textbook is incorrect?
Reply 3
Original post by captainslow12
So would you say the textbook is incorrect?


What text book is it
Original post by Ladkus
What text book is it


CGP AQA Physics year 2 (got pictures of magnetic fields around spheres on the cover)
Reply 5
Cgp is never wrong
Original post by Rhiaaaaa
Cgp is never wrong


So is the markscheme wrong? (Actually, there are mistakes. Apparently neutrons have zero binding energy according to the textbook)
Aqa is awkward when it comes to physics. It should be plus or minus half the range. Is it possible you misinterpreted the study guide?
Original post by kibi.coco
Aqa is awkward when it comes to physics. It should be plus or minus half the range. Is it possible you misinterpreted the study guide?


Actually I think you may be correct. Now that I've re-read, it says the uncertainty is the difference between the best gradient and worst i.e the average of the difference between the two worst gradients. Ha ha, cheers mate!

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