It is possible to enter or modify the normal curves of specific speech lists that are used for speech audiometry in quiet or in noise.

This is how to proceed:

(1) Select speech audiometry in the ribbon.  (2) click on Format.  (3) click on Manage Stimulus Material. (4) Select the list where you want to add or modify the norm curve. (5) Click on Edit. (6) Click on Edit normative data.

Now the Stimulus Normative Data window opens.

 Follow these steps to create a norm curve:

(1) double click on a line to edit it or to create a new curve; enter its name

(2) Pick a colour for that norm curve (as it will appear on the speech audiogram)
(3) Decide whether it is a norm curve for the speech test in quiet or in noise
(4) enter the curve by entering its (x,y) points.  
  • For a norm curve in quiet, X stands for the presentation level (dB SPL) and Y for the score
  • For a norm curve in noise, X stands for the S/N level (signal to noise level) of the stimulus and Y for the corresponding score
You may want to add a scientific reference to the source of this curve (5).

You can also watch this instructional video.