If 0 - 9, 10 - 19, 20 - 29, …., are the classes of a grouped frequency distribution, then the width of each class is :

1. 9

2. 9.5

3. 10

4. 9 or 10

If 10, 15, 20, … are respectively the mid-value of the classes of a grouped frequency distribution, then the class whole mid-value is 25 is :

1. 20 - 27

2. 22.5 - 27.5

3. 21.5 - 28.5

4. 21 - 28

The width of each class of a frequency distribution is 5. The upper boundary of the class whose class mark is 25 is :

1. 22

2. 22.5

3. 27

4. 27.5

Class marks of a distribution are: 47, 52, 57, 62, 67, 72, 77, 82. Class size of the given distribution is :

1. 5

2. 6

3. 7

4. 2