This article throws light upon the four main forms of frequency curves. The forms are: 1. Symmetrical Unimodal Curve 2. Moderately Asymmetrical (Skew) Distribution 3. Extremely Skew (J- Shaped) 4. U-Shaped or Antimodal Curves.
Form # 1. Symmetrical Unimodal Curve:
Point of maximum in the middle and the curve is symmetrical on both sides.
Form # 2. Moderately Asymmetrical (Skew) Distribution:
If there is no symmetry in the curve, it is called skew curve. Frequency falls more rapidly on one side of the maximum than on the other.
Form # 3. Extremely Skew (J- Shaped):
Maximum frequency is at one end of the distribution.
Form # 4. U-Shaped or Antimodal Curves:
In this type of curve, the maximum frequency is at the ends of the range and a maximum towards the centre. Rising frequencies on either side of the minimum.