Materiality

Hi

In answering the majority of the questions i have come across, they start of with determining whether the potential misstatement is material or not.

The BPP study text indicated that the materiality boundary is dependent to each company but gave a basis to which figures can be tested against;

Revenue between 1/2%-1%
Total assets between 1%-2%
PBT between 5%-10%

How do we decide what basis to use when determining whether a figure is material or not? Do we use the above or is there another way of determining this?

Thanks