Question

For a grouped frequency table there are 5 class-intervals. The fourth and fifth class intervals are '35 - 40' and '40 - 45' respectively. Find the first class interval.

• A. 20 - 25
• B. 15 - 20
• C. 5 - 10
• D. 25 - 30

Answer 1

The correct option is A 20 - 25

There are 5 classes.

The fifth class-interval = (40 - 45)

The fourth class-interval = (35 - 40)

From the given classes we can find the class-size as 5.

Class-Size = Upper class limit-Lower class limit
= 40-35
= 5

The third class-interval = (35-5 , 35)
= (30- 35)

The second class-interval = (30-5, 30)
= (25- 30)

The first class-inteval = (20-25, 25)
= (20 - 25)