Question

Make a frequency polygon from the given data.

$$\begin{array}{cc}Weight\left(kg\right)& NumberOfStudents\\ 35.5-40.5& 5\\ 40.5-45.5& 2\\ 45.5-50.5& 12\\ 50.5-55.5& 2\\ 55.5-60.5& 45\end{array}$$

Answer 1

A Frequency polygon is the graphical representation of both discrete and continuous frequency distribution.

Class marks are first calculated, then they are taken on the X-axis and the corresponding frequency on the Y-axis.

Weight(Kg)	Class Marks	Number of students
30.5 - 35.5	33	0
35.5 - 40.5	38	5
40.5 - 45.5	43	2
45.5 - 50.5	48	12
50.5 - 55.5	53	2
55.5 - 60.5	58	45
60.5 - 65.5	63	0

Scale used:
On X-axis 1 cm = 1 class interval length
On Y-axis 1 cm = 5 units

Although there exists no class preceding the lowest class and no class succeeding the highest class, addition of two class intervals with zero frequency makes the area of frequency polygon and area of the histogram as equal.