Question

Show the following data by a frequency polygon: 

Electricity Bill (₹)	Families (f)
200 - 400	240
400 - 600	300
600 - 800	450
800 - 1000	350
1000 - 1200	160

Hint:

A frequency polygon can be obtained by joining the mid-points of histogram rectangles, or directly by plotting class mid-points versus frequencies.

Answer 1

Step 1: Find the class mid-points. 

Mid-point (x) = (Upper class limit + Lower class limit) / 2 

Class Interval	Mid-point (x)	Frequency (f)
200 - 400	300	240
400 - 600	500	300
600 - 800	700	450
800 - 1000	900	350
1000 - 1200	1100	160

Step 2: Plot the points. 
On a graph paper: 
- Take class mid-points (x) on the X-axis. 
- Take frequencies (f) on the Y-axis. 
- Plot the points: (300, 240), (500, 300), (700, 450), (900, 350), (1100, 160). 

Step 3: Join these points by straight lines. 
To complete the polygon, join the first point to the previous mid-point (100, 0) and the last point to the next mid-point (1300, 0). 

Step 4: Conclusion. 
The resulting closed figure represents the Frequency Polygon for the given data. 

Final Answer: Frequency Polygon drawn with mid-points (300, 500, 700, 900, 1100).