I was just told the following:
The stopping criterion in the bisection method is $|b − a| < \epsilon$. However for most other algorithms it is is $|f(x)| < \epsilon$. These two stopping criteria are within a factor of approximately $|f'(x^*)|$ assuming $f$ is smooth and $\epsilon$ is small.
I'm confused by what "within a factor of approximately $|f'(x^*)|$" means and how to go about showing this.