Compute the critical value z a/2 that corresponds to a 93% level of confidence

Step 1: Calculate the 0.035 that you already know how to do.

Step 2: Calculate 1-0.035 = 0.965

Step 3: Look at the Z table and find 0.965 (or as close to this value as possible)

Step 4: Look at the far left of the row containing 0.965 1.8

Step 5: Look at the top of the column containing 0.965 0.01

Step 6: Add these two values 1.81

Step 6 is your z value that corresponds to that level of confidence.