Question

The class marks of a frequency distribution are 10, 20, 30, 40, 50; find the class size and class intervals.

Answer 1

The class marks are 10, 20, 30, 40, 50.

Step-wise calculation:

1. Class size = Difference between two consecutive class marks

= 20 – 10

= 10

2. Half class size

= `10/2`

= 5

3. For each class mark M.

Class interval = M – 5 to M + 5:

For 10: 10 – 5 to 10 + 5 = 5 – 15

For 20: 15 – 25

For 30: 25 – 35

For 40: 35 – 45

For 50: 45 – 55

Class size = 10

Class intervals = 5 – 15

15 – 25

25 – 35

35 – 45

45 – 55