You can evaluate your slug test using the HVORSLEV (1951) method. However, you should have first defined your preferences for this evaluation method as described in the next menu item.
A linear data curve appears on the screen. In addition, after selecting this menu item, the best-fit curve (e-function) is drawn using the HVORSLEV (1951) model approach. After pressing [F12] you will see the result of the evaluation for the best-fit curve.
You can achieve a clear presentation of the data curve and the best-fit curve by going to the menu items "Graphic preferences/Preferences" and "Graphic preferences/Pen colour and width" and specifying presentation preferences.