Calculating percentage uncertainty for young's modulus

[Hallam17]

Homework Statement

I cannot work out how to calculate my percentage uncertainty for my coursework, i need to show that my second method has a reduced uncertainty than my first, could anybody please enlighten me as to how to work it out. My table for one of the practicals is attached

Homework Equations

You probably know this already but just in case

∏d² = cross sectional area
Extension/Original Length = Strain
Force Applied/Cross Sectional Area = Stress
Young's Modulus = Stress/Strain

The Attempt at a Solution

Tried numerous times but quite simply don't understand how to get an overall uncertainty for the practical

I would also like to add that as stated in the 'why hasn't anybody answered me' thread it's the theory that I'm after not for you to do the homework, I understand how that could irritate those helping on here

Any help would be greatly appreciated, thanks

 

[Hallam17]

After refreshing this page for 2 hours, I tried yet even more possibilities and have figured out how to do this now!