Question

45 students across the different levels of Intelligent Quotient are distributed in the grouped table given below.

IQ	60-70	70-80	80-90	90-100	100-110	110-120	120-130
No. of patients	3	6	9	11	11	7	2

Draw the frequency polygon for the data.

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

We have to first calculate the class marks of all the classes.

Class intervals (Ages)	Frequency (No. of patients)	Class marks	Points
50-60	0	55	(55,0)
60-70	3	65	(65,3)
70-80	6	75	(75,6)
80-90	9	85	(85,9)
90-100	11	95	(95,11)
100-110	11	105	(105,11)
110-120	7	115	(115,7)
120-130	2	125	(125,2)
130-140	0	135	(135,0)

Take suitable scale ,
On X-axis 1 cm = class interval length
On Y-axis 1 cm = 2 units

Take class marks on X-axis and frequency on Y-axis
Now plot the points on the graph.