Histogram & Frequency Polygon

Steps:

(1) Select the class interval withthe minimum class size. In our case it is 4.

(2) The length of the rectangles are then modified  to be proportionate to the class size.

for class size 4, the length of the rectangle will be = ((frequency)/ class size) x (minimum class size)

= (5/4) x 4 = 5

for class size 6, the length of the rectangle will be = ((frequency)/ class size) x (minimum class size)

= (6/6) x 4 = 4

for class size 12, the length of the rectangle will be = ((frequency)/ class size) x (minimum class size)

= (9/12) x 4 =3

for class size 20, the length of the rectangle will be = ((frequency)/ class size) x (minimum class size)

= (25/20) x 4 = 5

for class size 28, the length of the rectangle will be = ((frequency)/ class size) x (minimum class size)

= (21/28) x 4 = 3

Now draw the hisogram using the new table which is:

Class Interval	10-14	14-20	20-32	32-52	52-80
Frequency	5	6	9	25	21
Width of the class	4	6	12	20	28
height of rectangles	5	4	3	5	3