Question

Why do we use a bell curve to assess the normality of a variable as opposed to a square, triangle, or some other symmetrical shape?

Answer 1

In Normal distribution, bell shaped curve is used to show the symmetry. Moreover many practical situations data shows a tendency to form a normal curve than any other shape if we try to depict the graphical distribution of data. This curve shows that most of the data is concentrated at the center and decreses on either side. The highest point on the curve represents the most probable event. The average of all data points is the mean and the data will lie within a range to the left or to the right of the mean, known as the standard deviation.