Solution
The class marks of the classes
20 – 29, 30 – 39, 40 – 49, 50 – 59, 60 – 69, 70 – 79 are 24.5, 34.5, 44.5, 54.5, 64.5, 74.5 respectively.
The corresponding frequencies for clubs A and B are 5, 10, 15, 10, 20, 5; 10, 15, 10, 5, 10, 15, respectively.
For the club A, the frequency polygon is drawn by joining the points (14.5, 0), (24.5, 5), (34.5, 10), (44.5, 15), (54.5, 10), (64.5, 20), (74.5, 5), (84.5, 0).
For the club B, the frequency polygon is drawn by joining the points (14.5, 0), (24.5, 10), (34.5, 15), (44.5, 10), (54.5, 5), (64.5, 10), (74.5, 15), (84.5, 0).
