Question

The class marks of a frequency distribution are 5, 10, 15, 20, 25, 30. The class corresponding to class mark 20 is ______.

पर्याय

• 17.5 – 22.5

• 17 – 23

• 15 – 25

• none of these

Answer 1

The class marks of a frequency distribution are 5, 10, 15, 20, 25, 30. The class corresponding to class mark 20 is 17.5 – 22.5.

Explanation:

The class-size = difference between successive class marks

= 10 – 5 

= 5

Half the class-size = 2.5.

So the class with midpoint 20 is 20 – 2.5 to 20 + 2.5 = 17.5 – 22.5.