Here is the question:

A machine is supposed to put 100 grams into a bag. If you know standard deviation (sigma) = 25 and you're testing at the 5% level of significance (i.e. alpha = 0.05), then find the power to find a change of 2 grams if sample size (n) is 100.

I have no idea on how to set this up or solve it. Here's the actual assignment. It is question 3 a).

Thanks a lot.