# Using the Z-Table in Reverse: from the regions to the Z-values

### From www.norsemathology.org

In a "forward direction" use of the Z-Table, you'll often

- Start with a normal distribution with mean and standard deviation
- Transform a value to a standard normal, to a standard , via
- Find an area value from the Z-Table, corresponding to .

In the "backward direction", you do these three steps in reverse:

- Starting with an area, you
- Find the corresponding of the area, considered as
- Transform the
*Z*-values from the standard normal to the original normal values, via the transformation