Question

A grouped frequency distribution table with classes of equal sizes using 63 – 72 (72 included) as one of the class is constructed for the following data:

30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88, 40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96, 102, 110, 88, 74, 112, 14, 34, 44.

The number of classes in the distribution will be:

Options

• 9

• 10

• 11

• 12

Answer 1

10

Explanation:

We arrange the given data into groups like 13 – 22, 23 – 32, 103 – 112. (since, our data is from 14 to 112).

The class width in this case is 9.

Now, the given data can be arranged in tabular form as follows

Class interval	Tally marks	Frequency
13 – 22	||||	4
23 – 32	||	2
33 – 42	|||	3
43 – 52	|||	3
53 – 62	|	1
63 – 72	||	2
73 – 82	`\cancel(||||)`	5
83 – 92	|||	3
93 – 102	|||	3
103 – 112	||||	4

Hence, the number of classes in distribution will be 10.