Determine the critical regions and critical values for z that would be used to test the null hypothesis at the given level of significance as described in each of the following.
A. HO: u = 73 Ha: u does not equal 73 a = 0.01
B. Ho: u > or = 90 Ha: u < 90 a = 0.10
C. Ho: u < 43 Ha: u > 43 a = 0.05