Matlab : Exploring the effects of co-efficient quantization
For each of the vectors "a" and "b", you need to find the element with the largest absolute magnitude. (I'm not sure of the specific Matlab code for this; probably something like max (abs (a)).)

Then, you need to pick the smallest number of the form 2N (N is an integer) that is larger than the value determined in the previous step.

From there, the rest of the instructions should be straightforward.