What is the difference between Frequency curve and frequency polygon?

A frequency polygon is a closed figure that is formed by joining the top midpoints of all the rectangles of histograms using a straight line. It can also be obtained by plotting the mid-points of the class intervals with their respective frequencies and joining the points with a straight line.On the other hand, frequency curve is a curve that is obtained by joining the top midpoints of all rectangles of a histogram using a free hand.

It should be noted that the only difference between a frequency curve and a frequency polygon is that while, frequency polygon is drawn by joining the points by a straight line, frequency curve is drawn by a smooth hand. In other words, when frequency polygon is smoothed out then it is known as frequency curve.