By means of the slider in the lower region of the graph, the parameters of the Gaussian distribution can be varied. The parameter range of the slider can be adjusted in the numeric field 'Range of the parameter'. The red dots on the bell curve can be shifted. For the area between the points, the integral of the bell curve is calculated. Since the total area of the Gaussian distribution is normalized to one so corresponds the integral to the area. That e.g. if the points be placed on ±σ then is is the area 0.68 or 68% of the total. With the 'lines Style' can be switched on the display of the derivative.