Draw a frequency polygon for the following data.Marks10–2020–3030–4040–5050–60No. of students51220158

Answer: Plot (5, 0), (15, 5), (25, 12), (35, 20), (45, 15), (55, 8), (65, 0) and join them by straight line segments.

Class marks: 15, 25, 35, 45, 55. Points (class mark, frequency): (15, 5), (25, 12), (35, 20), (45, 15), (55, 8).

To close the polygon, take one class before (0–10, mark 5) and one after (60–70, mark 65) with frequency 0: points (5, 0) and (65, 0).

Scale: X-axis 1 cm = 10 marks, Y-axis 1 cm = 2 students.

[Figure: frequency polygon joining (5,0), (15,5), (25,12), (35,20), (45,15), (55,8), (65,0); highest point at (35, 20).]