Question: how to do invnorm on ti 83?
Answer: Step 1: Press 2nd VARS 3. This displays InvNorm( on the home screen.
Step 2: Type one of the following: 0.05 (for a one tailed test) ... 
Step 3: Press the ) button.
Step 4: Press Enter.
Step 1: Press 2nd VARS 3. ... 
Step 2: Type . ... 
Step 3: Press the ) button.
Your display should read InvNorm(.