I don't understand how to determine the accuracy order of different numerical methods
I have two examples:
(1)
(2)
For the (1) I get that the quotient for the errors are $16$ and for (2) I get that the quotient is $4$. And from what my teacher says, knowing that the quotient is $4$ then, $2^2=4$ and so the accuracy order is $2$. So I assumed that the same goes for ex. (1) so $2^4=16$ so the accuracy order should be $4$, but the correct answer is $1$ which I don't understand.
Could someone please explain how to determine the accuracy order from the given data. Thank you!

